REST Component

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The REST Component can be used to retrieve XML documents from the World Wide Web.

Syntax

TipwREST

Remarks

The REST Component supports both plaintext and Secure Sockets Layer/Transport Layer Security (SSL/TLS) connections. When connecting over SSL/TLS the SSLServerAuthentication event allows you to check the server identity and other security attributes. The SSLStatus event provides information about the SSL handshake. Additional SSL related settings are also supported via the Config method.

The REST Component implements a standard REST client with the added option of SSL security.

The component contains a number of properties that map directly to HTTP request headers. All XML data received are parsed by the component and are provided to the user through properties, such as XPath, XElement, and XText, which allow for traversal of the document structure. The Header event will provide the HTTP headers as returned by the server.

To receive a document, call the Get method with the URL to retrieve the specified resource in the URL parameter. The component will automatically parse the XML data, depending on the content type that is returned. Call the Delete method to delete a resource specified by the URL parameter.

The Post and Put methods are used to create and update resources. Post is commonly used to both create and update resources; however, each service may have its own requirements. To send data to the server, set PostData and call the Post or Put method.

To add authorization credentials to an outgoing request, you should specify the User and Password properties. The REST Component supports basic, digest, and NTLM authentication through the AuthScheme property.

Property List

The following is the full list of the properties of the component with short descriptions. Click on the links for further details.

Method List

The following is the full list of the methods of the component with short descriptions. Click on the links for further details.

Event List

The following is the full list of the events fired by the component with short descriptions. Click on the links for further details.

Config Settings

The following is a list of config settings for the component with short descriptions. Click on the links for further details.

Accept Property (REST Component)

This property includes a list of acceptable MIME types for the request.

Syntax

property Accept: String read get_Accept write set_Accept;

Default Value

''

Remarks

If this property contains a nonempty string, an HTTP Accept header is added to the request.

The Accept header is used for content negotiation. It provides the server with a comma-separated list of MIME types that are acceptable for its response.

Authorization Property (REST Component)

This property includes the Authorization string to be sent to the server.

Syntax

property Authorization: String read get_Authorization write set_Authorization;

Default Value

''

Remarks

If the Authorization property contains a nonempty string, an Authorization HTTP request header is added to the request. This header conveys Authorization information to the server.

A common use for this property is to specify OAuth authorization string.

This property is provided so that the HTTP component can be extended with other security schemes in addition to the authorization schemes already implemented by the component.

The AuthScheme property defines the authentication scheme used. In the case of HTTP Basic Authentication (default), every time User and Password are set, they are Base64 encoded, and the result is put in the Authorization property in the form 'Basic [encoded-user-password]'.

AuthScheme Property (REST Component)

The authentication scheme to use when server authentication is required.

Syntax

property AuthScheme: TipwTHTTPAuthSchemes read get_AuthScheme write set_AuthScheme;

TipwTHTTPAuthSchemes = (
  authBasic,
  authDigest,
  authProprietary,
  authNone,
  authNtlm,
  authNegotiate,
  authOAuth
);

Default Value

authBasic

Remarks

This property will tell the component which type of authorization to perform when the User and Password properties are set.

This property should be set to authNone (3) when no authentication is to be performed.

By default, this property is authBasic (0), and if the User and Password properties are set, the component will attempt HTTP Basic Authentication. If AuthScheme is set to authDigest (1), authNtlm (4), or authNegotiate (5), then Digest, NTLM, or Windows Negotiate (Kerberos) authentication will be attempted instead.

If AuthScheme is set to authProprietary (2), then the authorization token must be supplied through the Authorization property.

If AuthScheme is set to authOAuth (6), then the authorization string must be supplied through the Authorization property.

Note: If you set the Authorization property and AuthScheme is not authProprietary or authOAuth, then the AuthScheme will be set automatically to authProprietary (2) by the component.

For security, changing the value of this property will cause the component to clear the values of User, Password, and Authorization.

BuildDOM Property (REST Component)

When True, an internal object model of the XML document is created.

Syntax

property BuildDOM: Boolean read get_BuildDOM write set_BuildDOM;

Default Value

true

Remarks

Set BuildDOM to True when you need to browse the current document through XPath.

Validate is automatically set to True when BuildDOM is set to True.

Connected Property (REST Component)

This shows whether the component is connected.

Syntax

property Connected: Boolean read get_Connected write set_Connected;

Default Value

false

Remarks

This property is used to determine whether or not the component is connected to the remote host.

Note: It is recommended to use the Connect or Disconnect method instead of setting this property.

This property is not available at design time.

ContentType Property (REST Component)

This property includes the content type for posts and puts.

Syntax

property ContentType: String read get_ContentType write set_ContentType;

Default Value

''

Remarks

If this property contains a nonempty string, a Content-Type HTTP request header is added to the request. The purpose of the header is to show the contents of the data during a Post or Put to the server.

The most common example is posting of HTML form input data. In that case, this property must be set to 'application/x-www-form-urlencoded'.

This property is not available at design time.

Cookies Property (REST Component)

This property includes a collection of cookies.

Syntax

property Cookies: TipwHTTPCookieList read get_Cookies write set_Cookies;

Remarks

This property contains a collection of cookies. To add cookies to outgoing HTTP requests, add cookies (of type HTTPCookie) to this collection.

To see cookies that are set by the server, use the SetCookie event, which displays the cookies and their properties as set by the server. Those cookies also are added to Cookies.

MaxHTTPCookies can be used to control the maximum number of cookies saved.

This property is not available at design time.

Firewall Property (REST Component)

A set of properties related to firewall access.

Syntax

property Firewall: TipwFirewall read get_Firewall write set_Firewall;

Remarks

This is a Firewall-type property, which contains fields describing the firewall through which the component will attempt to connect.

FollowRedirects Property (REST Component)

This property determines what happens when the server issues a redirect.

Syntax

property FollowRedirects: TipwTFollowRedirects read get_FollowRedirects write set_FollowRedirects;

TipwTFollowRedirects = (
  frNever,
  frAlways,
  frSameScheme
);

Default Value

frNever

Remarks

This property determines what happens when the server issues a redirect. Normally, the component returns an error if the server responds with an "Object Moved" message. If this property is set to frAlways (1), the new URL for the object is retrieved automatically every time.

If this property is set to frSameScheme (2), the new URL is retrieved automatically only if the URLScheme is the same; otherwise, the component raises an exception.

Note: Following the HTTP specification, unless this property is set to frAlways (1), automatic redirects will be performed only for GET or HEAD requests. Other methods potentially could change the conditions of the initial request and create security vulnerabilities.

Furthermore, if either the new URL server or port are different from the existing one, User and Password are also reset to empty. If, however, this property is set to frAlways (1), the same credentials are used to connect to the new server.

A Redirect event is fired for every URL the product is redirected to. In the case of automatic redirections, the Redirect event is a good place to set properties related to the new connection (e.g., new authentication parameters).

The default value is frNever (0). In this case, redirects are never followed, and the component raises an exception instead.

From Property (REST Component)

This property includes the email address of the HTTP agent (optional).

Syntax

property From: String read get_From write set_From;

Default Value

''

Remarks

This property contains the email address of the HTTP agent (optional). If it contains a nonempty string, an HTTP From: header is added to the request. This header generally gives the email address of the requester of the document.

This property is not available at design time.

HTTPMethod Property (REST Component)

This property includes the HTTP method used for the request.

Syntax

property HTTPMethod: String read get_HTTPMethod write set_HTTPMethod;

Default Value

''

Remarks

This property contains the HTTP method used for the request. If an empty string is provided, the HTTPMethod is determined automatically by the method being called. You may change it to a custom value if you require an HTTP method other than what is provided by the component. When providing a custom value, make the request by calling the Post method.

This property is not available at design time.

Idle Property (REST Component)

The current status of the component.

Syntax

property Idle: Boolean read get_Idle;

Default Value

true

Remarks

Idle will be False if the component is currently busy (communicating and/or waiting for an answer), and True at all other times.

This property is read-only.

IfModifiedSince Property (REST Component)

This property includes a date determining the maximum age of the desired document.

Syntax

property IfModifiedSince: String read get_IfModifiedSince write set_IfModifiedSince;

Default Value

''

Remarks

If this property contains a nonempty string, an If-Modified-Since HTTP header is added to the request. The value of this header is used to make the HTTP request conditional: If the requested documented has not been modified since the time specified in the field, a copy of the document will not be returned from the server; instead, a 304 (not modified) response will be returned by the server and the component raises an exception

The format of the date value for IfModifiedSince is detailed in the HTTP specs. An example is Sat, 29 Oct 1994 19:43:31 GMT.

This property is not available at design time.

LocalFile Property (REST Component)

This property includes the path to a local file for downloading. If the file exists, it is overwritten.

Syntax

property LocalFile: String read get_LocalFile write set_LocalFile;

Default Value

''

Remarks

This property is used when getting a document.

If this property is empty, then the received data are provided through TransferredData and the Transfer event.

LocalHost Property (REST Component)

The name of the local host or user-assigned IP interface through which connections are initiated or accepted.

Syntax

property LocalHost: String read get_LocalHost write set_LocalHost;

Default Value

''

Remarks

The LocalHost property contains the name of the local host as obtained by the gethostname() system call, or if the user has assigned an IP address, the value of that address.

In multi-homed hosts (machines with more than one IP interface) setting LocalHost to the value of an interface will make the component initiate connections (or accept in the case of server components) only through that interface.

If the component is connected, the LocalHost property shows the IP address of the interface through which the connection is made in internet dotted format (aaa.bbb.ccc.ddd). In most cases, this is the address of the local host, except for multi-homed hosts (machines with more than one IP interface).

NOTE: LocalHost is not persistent. You must always set it in code, and never in the property window.

Namespaces Property (REST Component)

This property includes a collection of namespaces in the current stack.

Syntax

property Namespaces: TipwXMLNamespaceList read get_Namespaces;

Remarks

This property contains a collection of XML namespaces, which are standards for providing uniquely named elements and attributes in an XML instance.

The default namespace is found at index 0.

This property is read-only and not available at design time.

OtherHeaders Property (REST Component)

This property includes other headers as determined by the user (optional).

Syntax

property OtherHeaders: String read get_OtherHeaders write set_OtherHeaders;

Default Value

''

Remarks

This property can be set to a string of headers to be appended to the HTTP request headers created from other properties like ContentType and From.

The headers must follow the format Header: Value as described in the HTTP specifications. Header lines should be separated by CRLF ('#13#10') .

Use this property with caution. If this property contains invalid headers, HTTP requests may fail.

This property is useful for extending the functionality of the component beyond what is provided.

This property is not available at design time.

ParsedHeaders Property (REST Component)

This property includes a collection of headers returned from the last request.

Syntax

property ParsedHeaders: TipwHeaderList read get_ParsedHeaders;

Remarks

This property contains a collection of headers returned from the last request. Whenever headers are returned from the server, the headers are parsed into a collection of headers. Each Header in this collection contains information describing that header.

MaxHeaders can be used to control the maximum number of headers saved.

This property is read-only and not available at design time.

Password Property (REST Component)

This property includes a password if authentication is to be used.

Syntax

property Password: String read get_Password write set_Password;

Default Value

''

Remarks

This property contains a password if authentication is to be used. If AuthScheme is set to HTTP Basic Authentication, the User and Password are Base64 encoded and the result is put in the Authorization configuration setting in the form 'Basic [encoded-user-password]'.

If AuthScheme is set to HTTP Digest Authentication, the User and Password properties are used to respond to the HTTP Digest Authentication challenge from the server.

If AuthScheme is set to NTLM, NTLM authentication will be attempted. If AuthScheme is set to NTLM and User and Password are empty, the component will attempt to authenticate using the current user's credentials.

PostData Property (REST Component)

This property includes the data to post with the URL if the POST method is used.

Syntax

property PostData: String read get_PostData write set_PostData;
property PostDataB: TBytes read get_PostDataB write set_PostDataB;

Default Value

''

Remarks

This property contains the data to post with the URL if the POST method is used. If this property contains a nonempty string, then if the HTTP POST method is used (Post method), the contents of this property are appended to the HTTP request after the HTTP headers.

An HTTP Content-Length header is also added to the request. Its value is the length of the string in PostData.

The most common example is posting of HTML form input data. In that case, the ContentType property must be set to application/x-www-form-urlencoded.

Example. Performing a Post:

HTTPControl.ContentType = "application/x-www-form-urlencoded" HTTPControl.PostData = "firstname=Tom&lastname=Thompson&country=US" HTTPControl.Post(myurl)

This property is not available at design time.

Proxy Property (REST Component)

A set of properties related to proxy access.

Syntax

property Proxy: TipwProxy read get_Proxy write set_Proxy;

Remarks

This property contains fields describing the proxy through which the component will attempt to connect.

Referer Property (REST Component)

This property includes the referer URL/document (optional).

Syntax

property Referer: String read get_Referer write set_Referer;

Default Value

''

Remarks

If this property contains a nonempty string, a Referer HTTP request header is added to the request. The purpose of the header is to show the document referring the requested URL.

This property is not available at design time.

SSLAcceptServerCertEncoded Property (REST Component)

This is the certificate (PEM/Base64 encoded).

Syntax

property SSLAcceptServerCertEncoded: String read get_SSLAcceptServerCertEncoded write set_SSLAcceptServerCertEncoded;
property SSLAcceptServerCertEncodedB: TBytes read get_SSLAcceptServerCertEncodedB write set_SSLAcceptServerCertEncodedB;

Default Value

''

Remarks

This is the certificate (PEM/Base64 encoded). This property is used to assign a specific certificate. The Store and Subject properties also may be used to specify a certificate.

When Encoded is set, a search is initiated in the current Store for the private key of the certificate. If the key is found, Subject is updated to reflect the full subject of the selected certificate; otherwise, Subject is set to an empty string.

This property is not available at design time.

SSLCertEncoded Property (REST Component)

This is the certificate (PEM/Base64 encoded).

Syntax

property SSLCertEncoded: String read get_SSLCertEncoded write set_SSLCertEncoded;
property SSLCertEncodedB: TBytes read get_SSLCertEncodedB write set_SSLCertEncodedB;

Default Value

''

Remarks

This is the certificate (PEM/Base64 encoded). This property is used to assign a specific certificate. The Store and Subject properties also may be used to specify a certificate.

When Encoded is set, a search is initiated in the current Store for the private key of the certificate. If the key is found, Subject is updated to reflect the full subject of the selected certificate; otherwise, Subject is set to an empty string.

This property is not available at design time.

SSLCertStore Property (REST Component)

This is the name of the certificate store for the client certificate.

Syntax

property SSLCertStore: String read get_SSLCertStore write set_SSLCertStore;
property SSLCertStoreB: TBytes read get_SSLCertStoreB write set_SSLCertStoreB;

Default Value

'MY'

Remarks

This is the name of the certificate store for the client certificate.

The StoreType property denotes the type of the certificate store specified by Store. If the store is password protected, specify the password in StorePassword.

Store is used in conjunction with the Subject property to specify client certificates. If Store has a value, and Subject or Encoded is set, a search for a certificate is initiated. Please see the Subject property for details.

Designations of certificate stores are platform dependent.

The following designations are the most common User and Machine certificate stores in Windows:

When the certificate store type is PFXFile, this property must be set to the name of the file. When the type is PFXBlob, the property must be set to the binary contents of a PFX file (i.e., PKCS#12 certificate store).

SSLCertStorePassword Property (REST Component)

If the type of certificate store requires a password, this property is used to specify the password needed to open the certificate store.

Syntax

property SSLCertStorePassword: String read get_SSLCertStorePassword write set_SSLCertStorePassword;

Default Value

''

Remarks

If the type of certificate store requires a password, this property is used to specify the password needed to open the certificate store.

SSLCertStoreType Property (REST Component)

This is the type of certificate store for this certificate.

Syntax

property SSLCertStoreType: TipwCertStoreTypes read get_SSLCertStoreType write set_SSLCertStoreType;

TipwCertStoreTypes = (
  cstUser,
  cstMachine,
  cstPFXFile,
  cstPFXBlob,
  cstJKSFile,
  cstJKSBlob,
  cstPEMKeyFile,
  cstPEMKeyBlob,
  cstPublicKeyFile,
  cstPublicKeyBlob,
  cstSSHPublicKeyBlob,
  cstP7BFile,
  cstP7BBlob,
  cstSSHPublicKeyFile,
  cstPPKFile,
  cstPPKBlob,
  cstXMLFile,
  cstXMLBlob,
  cstJWKFile,
  cstJWKBlob,
  cstSecurityKey,
  cstBCFKSFile,
  cstBCFKSBlob,
  cstPKCS11,
  cstAuto
);

Default Value

cstUser

Remarks

This is the type of certificate store for this certificate.

The component supports both public and private keys in a variety of formats. When the cstAuto value is used, the component will automatically determine the type. This property can take one of the following values:

SSLCertSubject Property (REST Component)

This is the subject of the certificate used for client authentication.

Syntax

property SSLCertSubject: String read get_SSLCertSubject write set_SSLCertSubject;

Default Value

''

Remarks

This is the subject of the certificate used for client authentication.

This property must be set after all other certificate properties are set. When this property is set, a search is performed in the current certificate store to locate a certificate with a matching subject.

If a matching certificate is found, the property is set to the full subject of the matching certificate.

If an exact match is not found, the store is searched for subjects containing the value of the property.

If a match is still not found, the property is set to an empty string, and no certificate is selected.

The special value "*" picks a random certificate in the certificate store.

The certificate subject is a comma-separated list of distinguished name fields and values. For instance, "CN=www.server.com, OU=test, C=US, E=support@nsoftware.com". Common fields and their meanings are as follows:

If a field value contains a comma, it must be quoted.

SSLProvider Property (REST Component)

This specifies the SSL/TLS implementation to use.

Syntax

property SSLProvider: TipwTSSLProviders read get_SSLProvider write set_SSLProvider;

TipwTSSLProviders = (
  sslpAutomatic,
  sslpPlatform,
  sslpInternal
);

Default Value

sslpAutomatic

Remarks

This property specifies the SSL/TLS implementation to use. In most cases the default value of 0 (Automatic) is recommended and should not be changed. When set to 0 (Automatic) the component will select whether to use the platform implementation or the internal implementation depending on the operating system as well as the TLS version being used.

Possible values are:

In most cases using the default value (Automatic) is recommended. The component will select a provider depending on the current platform.

When Automatic is selected, on Windows the component will use the platform implementation. On Linux/macOS the component will use the internal implementation. When TLS 1.3 is enabled via SSLEnabledProtocols the internal implementation is used on all platforms.

SSLServerCertEncoded Property (REST Component)

This is the certificate (PEM/Base64 encoded).

Syntax

property SSLServerCertEncoded: String read get_SSLServerCertEncoded;
property SSLServerCertEncodedB: TBytes read get_SSLServerCertEncodedB;

Default Value

''

Remarks

This is the certificate (PEM/Base64 encoded). This property is used to assign a specific certificate. The Store and Subject properties also may be used to specify a certificate.

When Encoded is set, a search is initiated in the current Store for the private key of the certificate. If the key is found, Subject is updated to reflect the full subject of the selected certificate; otherwise, Subject is set to an empty string.

This property is read-only and not available at design time.

StatusLine Property (REST Component)

This property is the first line of the last server response.

Syntax

property StatusLine: String read get_StatusLine;

Default Value

''

Remarks

This property contains the first line of the last server response. This value can be used for diagnostic purposes. If an HTTP error is returned when calling a method of the component, the error string is the same as the StatusLine property.

The HTTP protocol specifies the structure of the StatusLine as follows: [HTTP version] [Result Code] [Description].

This property is read-only and not available at design time.

Timeout Property (REST Component)

A timeout for the component.

Syntax

property Timeout: Integer read get_Timeout write set_Timeout;

Default Value

60

Remarks

If the Timeout property is set to 0, all operations will run uninterrupted until successful completion or an error condition is encountered.

If Timeout is set to a positive value, the component will wait for the operation to complete before returning control.

The component will use DoEvents to enter an efficient wait loop during any potential waiting period, making sure that all system events are processed immediately as they arrive. This ensures that the host application does not "freeze" and remains responsive.

If Timeout expires, and the operation is not yet complete, the component raises an exception.

Please note that by default, all timeouts are inactivity timeouts, i.e. the timeout period is extended by Timeout seconds when any amount of data is successfully sent or received.

The default value for the Timeout property is 60 seconds.

TransferredData Property (REST Component)

This property includes the content of the last response from the server.

Syntax

property TransferredData: String read get_TransferredData;
property TransferredDataB: TBytes read get_TransferredDataB;

Default Value

''

Remarks

This property contains the content of the last response from the server. If the LocalFile is empty, data are accumulated in TransferredData, and also can be received in the Transfer event. Otherwise, this property returns an empty string.

TransferredDataLimit controls the maximum amount of data accumulated in this property (by default, there is no limit).

This property is read-only and not available at design time.

TransferredDataLimit Property (REST Component)

This property includes the maximum number of bytes of data to be transferred.

Syntax

property TransferredDataLimit: Int64 read get_TransferredDataLimit write set_TransferredDataLimit;

Default Value

0

Remarks

This property defines the maximum number of bytes of data to be transferred. The default value is zero, which means there is no limit to the amount of data the component will accumulate and parse. If this value is set to a number n that is greater than zero, the component will receive only the first n bytes of data from the server.

TransferredHeaders Property (REST Component)

This property includes the full set of headers as received from the server.

Syntax

property TransferredHeaders: String read get_TransferredHeaders;

Default Value

''

Remarks

This property returns the complete set of raw headers as received from the server.

The Header event shows the individual headers as parsed by the component.

This property is read-only and not available at design time.

URL Property (REST Component)

This property includes the URL to which the information is posted.

Syntax

property URL: String read get_URL write set_URL;

Default Value

''

Remarks

This property specifies the web page to which to post the form data. It is the same as the value specified by <FORM ACTION=...> in HTML forms.

User Property (REST Component)

This property includes a user name if authentication is to be used.

Syntax

property User: String read get_User write set_User;

Default Value

''

Remarks

This property contains a user name if authentication is to be used. If AuthScheme is set to HTTP Basic Authentication, The User and Password are Base64 encoded, and the result is put in the Authorization property in the form 'Basic [encoded-user-password]'.

If AuthScheme is set to HTTP Digest Authentication, the User and Password properties are used to respond to the HTTP Digest Authentication challenge from the server.

If AuthScheme is set to NTLM, NTLM authentication will be attempted. If AuthScheme is set to NTLM, and User and Password are empty, the component will attempt to authenticate using the current user's credentials.

Validate Property (REST Component)

This property controls whether documents are validated during parsing.

Syntax

property Validate: Boolean read get_Validate write set_Validate;

Default Value

true

Remarks

When True (default) the document will be validated during parsing. To disable validation set Validate to False. Disabling validation may be useful in cases where data can still be parsed even if the document is not well-formed.

XAttributes Property (REST Component)

A collection of attributes of the current element.

Syntax

property XAttributes: TipwXMLAttributeList read get_XAttributes;

Remarks

This collection consists of all attributes of the current XML element. The component parses each attribute into a collection of XMLAttribute types.

This property is read-only and not available at design time.

XChildren Property (REST Component)

Collection of child elements of the current element.

Syntax

property XChildren: TipwXMLElementList read get_XChildren;

Remarks

The elements are provided in the collection in the same order they are found in the document.

This property is read-only and not available at design time.

XElement Property (REST Component)

This property includes the name of the current element.

Syntax

property XElement: String read get_XElement;

Default Value

''

Remarks

The current element is specified in the XPath property.

This property is read-only.

XErrorPath Property (REST Component)

This property includes the XPath to check the server response for errors.

Syntax

property XErrorPath: String read get_XErrorPath write set_XErrorPath;

Default Value

''

Remarks

This property contains an XPath to check the server response for errors. If the XPath exists, an exception will be thrown containing the value of the element at the path.

XNamespace Property (REST Component)

This property includes the namespace of the current element.

Syntax

property XNamespace: String read get_XNamespace;

Default Value

''

Remarks

The current element is specified in the XPath property.

This property is read-only.

XParent Property (REST Component)

The parent of the current element.

Syntax

property XParent: String read get_XParent;

Default Value

''

Remarks

The current element is specified via the XPath property.

This property is read-only.

XPath Property (REST Component)

This property provides a way to point to a specific element in the response.

Syntax

property XPath: String read get_XPath write set_XPath;

Default Value

''

Remarks

This property provides a way to point to a specific element in the response. This property implements a subset of the XML XPath specification, which allows you to point to specific elements in the XML documents.

The path is a series of one or more element accessors separated by "/". The path can be absolute (starting with "/") or relative to the current XPath location.

Following are the possible values for an element accessor:

BuildDOM must be set to True before parsing the document for the XPath functionality to be available.

Example 1. Setting XPath:

XPrefix Property (REST Component)

This property includes the prefix of the current element.

Syntax

property XPrefix: String read get_XPrefix;

Default Value

''

Remarks

The current element is specified in the XPath property.

This property is read-only.

XSubTree Property (REST Component)

A snapshot of the current element in the document.

Syntax

property XSubTree: String read get_XSubTree;

Default Value

''

Remarks

The current element is specified via the XPath property. In order for this property to work you must have the CacheContent set to true.

This property is read-only.

XText Property (REST Component)

This property includes the text of the current element.

Syntax

property XText: String read get_XText;

Default Value

''

Remarks

The current element is specified in the XPath property.

This property is read-only.

AddCookie Method (REST Component)

This method adds a cookie and the corresponding value to the outgoing request headers.

Syntax

procedure AddCookie(CookieName: String; CookieValue: String);

Remarks

This property adds a cookie and the corresponding value to the outgoing request headers. Please refer to the Cookies property for more information on cookies and how they are managed.

Attr Method (REST Component)

This method returns the value of the specified attribute.

Syntax

function Attr(AttrName: String): String;

Remarks

If the attribute does not exist, an empty string is returned if ErrorOnEmptyAttr is set to False; otherwise, an exception is thrown.

Please refer to the XAttributes properties for more information.

Config Method (REST Component)

Sets or retrieves a configuration setting.

Syntax

function Config(ConfigurationString: String): String;

Remarks

Config is a generic method available in every component. It is used to set and retrieve configuration settings for the component.

These settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the component, access to these internal properties is provided through the Config method.

To set a configuration setting named PROPERTY, you must call Config("PROPERTY=VALUE"), where VALUE is the value of the setting expressed as a string. For boolean values, use the strings "True", "False", "0", "1", "Yes", or "No" (case does not matter).

To read (query) the value of a configuration setting, you must call Config("PROPERTY"). The value will be returned as a string.

Delete Method (REST Component)

This method deletes an object on the server.

Syntax

procedure Delete(URL: String);

Remarks

This method is used to delete an object at the URL specified by using the HTTP DELETE method. The server response text is received through the Transfer event, and the HTTP response headers through the Header event. If LocalFile is not empty, the data (not the headers) are written there as well. Normally, the user should have assigned correct values to User and Password or Authorization.

DoEvents Method (REST Component)

Processes events from the internal message queue.

Syntax

procedure DoEvents();

Remarks

When DoEvents is called, the component processes any available events. If no events are available, it waits for a preset period of time, and then returns.

Get Method (REST Component)

This method fetches the document using the HTTP GET method.

Syntax

procedure Get(URL: String);

Remarks

This method fetches the document using the HTTP GET method. The document contents are delivered to the component and parsed. The XPath, XElement, and XText or the TransferredData property then can be used to traverse the data. The HTTP response headers are returned through the Header event. If LocalFile is not empty, the data (not the headers) are written there as well.

HasXPath Method (REST Component)

Determines whether a specific element exists in the document.

Syntax

function HasXPath(XPath: String): Boolean;

Remarks

This method determines whether a particular XPath exists within the document. This may be used to check if a path exists before setting it via XPath.

This method returns True if the xpath exists, False if not.

See XPath for details on the XPath syntax.

Interrupt Method (REST Component)

Interrupt the current method.

Syntax

procedure Interrupt();

Remarks

If there is no method in progress, Interrupt simply returns, doing nothing.

Post Method (REST Component)

This method posts data to the HTTP server using the HTTP POST method.

Syntax

procedure Post(URL: String);

Remarks

This method posts data to the HTTP server using the HTTP POST method. The data to post are taken from the PostData property.

The server response text is parsed by the component, and may be accessed through properties like XPath, XElement, and XText or the TransferredData property. The HTTP response headers are received through the Header event. If LocalFile is not empty, the data (not the headers) are written there as well.

Put Method (REST Component)

This method sends data to the HTTP server using the HTTP PUT method.

Syntax

procedure Put(URL: String);

Remarks

This method sends data to the HTTP server using the HTTP PUT method. The data are taken from the PostData property.

The server response text is parsed by the component, and may be accessed using properties like XPath, XElement, and XText or the TransferredData property. The HTTP response headers are received through the Header event. If LocalFile is not empty, the data (not the headers) are written there as well.

The user normally should have assigned correct values to User and Password or Authorization.

Reset Method (REST Component)

This method resets the component.

Syntax

procedure Reset();

Remarks

This method resets all HTTP headers to default values and resets the XML parser.

TryXPath Method (REST Component)

Navigates to the specified XPath if it exists.

Syntax

function TryXPath(xpath: String): Boolean;

Remarks

This method will attempt to navigate to the specified XPath parameter if it exists within the document.

If the XPath exists the XPath property will be updated and this method returns True.

If the XPath does not exist the XPath property is not updated and this method returns False.

Characters Event (REST Component)

Fired for plain text segments of the input stream.

Syntax

type TCharactersEvent = procedure (
  Sender: TObject;
  const Text: String
) of Object;

property OnCharacters: TCharactersEvent read FOnCharacters write FOnCharacters;

Remarks

The Characters event provides the plain text content of the XML document (i.e. the text inside the tags). The text is provided through the Text parameter.

The text includes white space as well as end of line characters, except for ignorable whitespace which is fired through the IgnorableWhitespace event.

Comment Event (REST Component)

Fired when a comment section is encountered.

Syntax

type TCommentEvent = procedure (
  Sender: TObject;
  const Text: String
) of Object;

property OnComment: TCommentEvent read FOnComment write FOnComment;

Remarks

The Comment event is fired whenever a comment section (<!-- ..text... -->) is found in the document.

The full text of the comment is provided by the Text parameter.

Connected Event (REST Component)

This event is fired immediately after a connection completes (or fails).

Syntax

type TConnectedEvent = procedure (
  Sender: TObject;
  StatusCode: Integer;
  const Description: String
) of Object;

property OnConnected: TConnectedEvent read FOnConnected write FOnConnected;

Remarks

If the connection is made normally, StatusCode is 0 and Description is 'OK'.

If the connection fails, StatusCode has the error code returned by the Transmission Control Protocol (TCP)/IP stack. Description contains a description of this code. The value of StatusCode is equal to the value of the error.

Please refer to the Error Codes section for more information.

ConnectionStatus Event (REST Component)

This event is fired to indicate changes in the connection state.

Syntax

type TConnectionStatusEvent = procedure (
  Sender: TObject;
  const ConnectionEvent: String;
  StatusCode: Integer;
  const Description: String
) of Object;

property OnConnectionStatus: TConnectionStatusEvent read FOnConnectionStatus write FOnConnectionStatus;

Remarks

The ConnectionStatus event is fired when the connection state changes: for example, completion of a firewall or proxy connection or completion of a security handshake.

The ConnectionEvent parameter indicates the type of connection event. Values may include the following:

Disconnected Event (REST Component)

This event is fired when a connection is closed.

Syntax

type TDisconnectedEvent = procedure (
  Sender: TObject;
  StatusCode: Integer;
  const Description: String
) of Object;

property OnDisconnected: TDisconnectedEvent read FOnDisconnected write FOnDisconnected;

Remarks

If the connection is broken normally, StatusCode is 0 and Description is 'OK'.

If the connection is broken for any other reason, StatusCode has the error code returned by the Transmission Control Protocol (TCP/IP) subsystem. Description contains a description of this code. The value of StatusCode is equal to the value of the TCP/IP error.

Please refer to the Error Codes section for more information.

EndElement Event (REST Component)

Fired when an end-element tag is encountered.

Syntax

type TEndElementEvent = procedure (
  Sender: TObject;
  const Namespace: String;
  const Element: String;
  const QName: String;
  IsEmpty: Boolean
) of Object;

property OnEndElement: TEndElementEvent read FOnEndElement write FOnEndElement;

Remarks

The EndElement event is fired when an end-element tag is found in the document.

The element name is provided by the Element parameter.

The IsEmpty parameter is true when the event corresponds with an empty element declaration.

EndPrefixMapping Event (REST Component)

Fired when leaving the scope of a namespace declaration.

Syntax

type TEndPrefixMappingEvent = procedure (
  Sender: TObject;
  const Prefix: String
) of Object;

property OnEndPrefixMapping: TEndPrefixMappingEvent read FOnEndPrefixMapping write FOnEndPrefixMapping;

Remarks

The StartPrefixMapping event is fired when entering the scope of a namespace declaration.

EndTransfer Event (REST Component)

This event is fired when a document finishes transferring.

Syntax

type TEndTransferEvent = procedure (
  Sender: TObject;
  Direction: Integer
) of Object;

property OnEndTransfer: TEndTransferEvent read FOnEndTransfer write FOnEndTransfer;

Remarks

The EndTransfer event is fired first when the client finishes sending data to the server (in a POST or PUT request) and then when the document text finishes transferring from the server to the local host.

The Direction parameter shows whether the client (0) or the server (1) is sending the data.

Error Event (REST Component)

Fired when information is available about errors during data delivery.

Syntax

type TErrorEvent = procedure (
  Sender: TObject;
  ErrorCode: Integer;
  const Description: String
) of Object;

property OnError: TErrorEvent read FOnError write FOnError;

Remarks

The Error event is fired in case of exceptional conditions during message processing. Normally the component raises an exception.

The ErrorCode parameter contains an error code, and the Description parameter contains a textual description of the error. For a list of valid error codes and their descriptions, please refer to the Error Codes section.

EvalEntity Event (REST Component)

Fired every time an entity needs to be evaluated.

Syntax

type TEvalEntityEvent = procedure (
  Sender: TObject;
  const Entity: String;
  var Value: String
) of Object;

property OnEvalEntity: TEvalEntityEvent read FOnEvalEntity write FOnEvalEntity;

Remarks

The Value parameter contains a suggested value for the entity (normally the entity name itself). You may set Value to a value of your choice, which will be later passed into the text stream.

Header Event (REST Component)

This event is fired every time a header line comes in.

Syntax

type THeaderEvent = procedure (
  Sender: TObject;
  const Field: String;
  const Value: String
) of Object;

property OnHeader: THeaderEvent read FOnHeader write FOnHeader;

Remarks

The Field parameter contains the name of the HTTP header (which is the same as it is delivered). The Value parameter contains the header contents.

If the header line being retrieved is a continuation header line, then the Field parameter contains '' (empty string).

IgnorableWhitespace Event (REST Component)

Fired when a section of ignorable whitespace is encountered.

Syntax

type TIgnorableWhitespaceEvent = procedure (
  Sender: TObject;
  const Text: String
) of Object;

property OnIgnorableWhitespace: TIgnorableWhitespaceEvent read FOnIgnorableWhitespace write FOnIgnorableWhitespace;

Remarks

The ignorable whitespace section is provided by the Text parameter.

Log Event (REST Component)

This event fires once for each log message.

Syntax

type TLogEvent = procedure (
  Sender: TObject;
  LogLevel: Integer;
  const Message: String;
  const LogType: String
) of Object;

property OnLog: TLogEvent read FOnLog write FOnLog;

Remarks

This event fires once for each log message generated by the component. The verbosity is controlled by the LogLevel setting.

LogLevel indicates the level of message. Possible values are as follows:

The value 1 (Info) logs basic information, including the URL, HTTP version, and status details.

The value 2 (Verbose) logs additional information about the request and response.

The value 3 (Debug) logs the headers and body for both the request and response, as well as additional debug information (if any).

Message is the log entry.

LogType identifies the type of log entry. Possible values are as follows:

• "Info"
• "RequestHeaders"
• "ResponseHeaders"
• "RequestBody"
• "ResponseBody"
• "ProxyRequest"
• "ProxyResponse"
• "FirewallRequest"
• "FirewallResponse"

Meta Event (REST Component)

Fired when a meta section is encountered.

Syntax

type TMetaEvent = procedure (
  Sender: TObject;
  const Text: String
) of Object;

property OnMeta: TMetaEvent read FOnMeta write FOnMeta;

Remarks

The Meta event is fired whenever a meta information section (<! ..text... >) is found in the document.

The full text of the meta section is provided by the Text parameter.

PI Event (REST Component)

Fired when a processing instruction section is encountered.

Syntax

type TPIEvent = procedure (
  Sender: TObject;
  const Text: String
) of Object;

property OnPI: TPIEvent read FOnPI write FOnPI;

Remarks

The PI event is fired whenever a processing instruction section (<? ..text... ?>) is found in the document.

The full text of the processing instruction is provided by the Text parameter.

Redirect Event (REST Component)

This event is fired when a redirection is received from the server.

Syntax

type TRedirectEvent = procedure (
  Sender: TObject;
  const Location: String;
  var Accept: Boolean
) of Object;

property OnRedirect: TRedirectEvent read FOnRedirect write FOnRedirect;

Remarks

This event is fired in cases in which the client can decide whether or not to continue with the redirection process. The Accept parameter is always True by default, but if you do not want to follow the redirection, Accept may be set to False, in which case the component raises an exception. Location is the location to which the client is being redirected. Further control over redirection is provided in the FollowRedirects property.

SetCookie Event (REST Component)

This event is fired for every cookie set by the server.

Syntax

type TSetCookieEvent = procedure (
  Sender: TObject;
  const Name: String;
  const Value: String;
  const Expires: String;
  const Domain: String;
  const Path: String;
  Secure: Boolean
) of Object;

property OnSetCookie: TSetCookieEvent read FOnSetCookie write FOnSetCookie;

Remarks

The SetCookie event is fired for every Set-Cookie: header received from the HTTP server.

The Name parameter contains the name of the cookie, with the corresponding value supplied in the Value parameter.

The Expires parameter contains an expiration time for the cookie (if provided by the server). The time format used is "Weekday, DD-Mon-YY HH:MM:SS GMT". If the server does not provide an expiration time, the Expires parameter will be an empty string. In this case, the convention is to drop the cookie at the end of the session.

The Domain parameter contains a domain name to limit the cookie to (if provided by the server). If the server does not provide a domain name, the Domain parameter will be an empty string. The convention in this case is to use the server specified in the URL (URLServer) as the cookie domain.

The Path parameter contains a path name to limit the cookie to (if provided by the server). If the server does not provide a cookie path, the Path parameter will be an empty string. The convention in this case is to use the path specified in the URL (URLPath) as the cookie path.

The Secure parameter specifies whether the cookie is secure. If the value of this parameter is True, the cookie value must be submitted only through a secure (HTTPS) connection.

SpecialSection Event (REST Component)

Fired when a special section is encountered.

Syntax

type TSpecialSectionEvent = procedure (
  Sender: TObject;
  const SectionId: String;
  const Text: String
) of Object;

property OnSpecialSection: TSpecialSectionEvent read FOnSpecialSection write FOnSpecialSection;

Remarks

The SpecialSection event is fired whenever a special section (such as <![ CDATA [ ..text... ]]>) is found in the document.

The full text of the special section is provided by the Text parameter, while the SectionId parameter provides the section identifier (e.g. "CDATA").

SSLServerAuthentication Event (REST Component)

Fired after the server presents its certificate to the client.

Syntax

type TSSLServerAuthenticationEvent = procedure (
  Sender: TObject;
  CertEncoded: String;
  CertEncodedB: TBytes;
  const CertSubject: String;
  const CertIssuer: String;
  const Status: String;
  var Accept: Boolean
) of Object;

property OnSSLServerAuthentication: TSSLServerAuthenticationEvent read FOnSSLServerAuthentication write FOnSSLServerAuthentication;

Remarks

During this event, the client can decide whether or not to continue with the connection process. The Accept parameter is a recommendation on whether to continue or close the connection. This is just a suggestion: application software must use its own logic to determine whether or not to continue.

When Accept is False, Status shows why the verification failed (otherwise, Status contains the string OK). If it is decided to continue, you can override and accept the certificate by setting the Accept parameter to True.

SSLStatus Event (REST Component)

Fired when secure connection progress messages are available.

Syntax

type TSSLStatusEvent = procedure (
  Sender: TObject;
  const Message: String
) of Object;

property OnSSLStatus: TSSLStatusEvent read FOnSSLStatus write FOnSSLStatus;

Remarks

The event is fired for informational and logging purposes only. This event tracks the progress of the connection.

StartElement Event (REST Component)

Fired when a begin-element tag is encountered in the document.

Syntax

type TStartElementEvent = procedure (
  Sender: TObject;
  const Namespace: String;
  const Element: String;
  const QName: String;
  IsEmpty: Boolean
) of Object;

property OnStartElement: TStartElementEvent read FOnStartElement write FOnStartElement;

Remarks

The StartElement event is fired when a begin-element tag is found in the document.

The element name is provided through the Element parameter. The attribute names and values (if any) are provided through the Name, Namespace, Prefix, and Value properties.

The IsEmpty parameter is true when the event corresponds with an empty element declaration.

StartPrefixMapping Event (REST Component)

Fired when entering the scope of a namespace declaration.

Syntax

type TStartPrefixMappingEvent = procedure (
  Sender: TObject;
  const Prefix: String;
  const URI: String
) of Object;

property OnStartPrefixMapping: TStartPrefixMappingEvent read FOnStartPrefixMapping write FOnStartPrefixMapping;

Remarks

The EndPrefixMapping event is fired when leaving the scope of a namespace declaration.

StartTransfer Event (REST Component)

This event is fired when a document starts transferring (after the headers).

Syntax

type TStartTransferEvent = procedure (
  Sender: TObject;
  Direction: Integer
) of Object;

property OnStartTransfer: TStartTransferEvent read FOnStartTransfer write FOnStartTransfer;

Remarks

The StartTransfer event is fired first when the client starts sending data to the server (in a POST or PUT request) and then when the document text starts transferring from the server to the local host.

The Direction parameter shows whether the client (0) or the server (1) is sending the data.

Status Event (REST Component)

This event is fired when the HTTP status line is received from the server.

Syntax

type TStatusEvent = procedure (
  Sender: TObject;
  const HTTPVersion: String;
  StatusCode: Integer;
  const Description: String
) of Object;

property OnStatus: TStatusEvent read FOnStatus write FOnStatus;

Remarks

HTTPVersion is a string containing the HTTP version string as returned from the server (e.g., "1.1").

StatusCode contains the HTTP status code (e.g., 200), and Description the associated message returned by the server (e.g., "OK").

Transfer Event (REST Component)

This event is fired while a document transfers (delivers document).

Syntax

type TTransferEvent = procedure (
  Sender: TObject;
  Direction: Integer;
  BytesTransferred: Int64;
  PercentDone: Integer;
  Text: String;
  TextB: TBytes
) of Object;

property OnTransfer: TTransferEvent read FOnTransfer write FOnTransfer;

Remarks

The Text parameter contains the portion of the document text being received. It is empty if data are being posted to the server.

The BytesTransferred parameter contains the number of bytes transferred in this Direction since the beginning of the document text (excluding HTTP response headers).

The Direction parameter shows whether the client (0) or the server (1) is sending the data.

The PercentDone parameter shows the progress of the transfer in the corresponding direction. If PercentDone can not be calculated the value will be -1.

Note: Events are not re-entrant. Performing time-consuming operations within this event will prevent it from firing again in a timely manner and may affect overall performance.

Firewall Type

The firewall the component will connect through.

Remarks

When connecting through a firewall, this type is used to specify different properties of the firewall, such as the firewall Host and the FirewallType.

Fields

Constructors

constructor Create();

Header Type

This is an HTTP header as it is received from the server.

Remarks

When a header is received through a Header event, it is parsed into a Header type. This type contains a Field, and its corresponding Value.

Fields

Constructors

constructor Create();

constructor Create(valField: String; valValue: String);

HTTPCookie Type

An HTTP cookie can be either sent to or received from the server.

Remarks

An HTTP cookie can store the cookies that are to be sent to the server. It also may store the cookies sent by the server.

Cookies that are to be sent to the server must have the Name and Value fields supplied before submitting the URL. When the SetCookie event is fired, however, all of the fields of an HTTPCookie are filled out accordingly.

Fields

Constructors

constructor Create();

constructor Create(valName: String; valValue: String);

Proxy Type

The proxy the component will connect to.

Remarks

When connecting through a proxy, this type is used to specify different properties of the proxy, such as the Server and the AuthScheme.

Fields

Constructors

constructor Create();

constructor Create(valServer: String; valPort: Integer);

constructor Create(valServer: String; valPort: Integer; valUser: String; valPassword: String);

XMLAttribute Type

An XML attribute from the current XML element.

Remarks

This type describes an XML attribute from the current element. It includes fields to denote information about the attribute being defined.

Fields

Constructors

constructor Create();

XMLElement Type

An element contained within the XML document.

Remarks

This type describes an XML element. The fields for this type describe the element Name, Prefix, and Namespace of the given element.

The elements are inserted into the array in the same order they are found in the document.

Fields

Constructors

constructor Create();

XMLNamespace Type

An XML namespace from the current namespace stack.

Remarks

This type describes an XML namespace from the current stack. It includes fields to denote the Prefix and the URI of the namespace being defined.

The default namespace exists at index 0. The Prefix field at index 0 is "xmlns", and the Name field contains the default namespace.

Fields

Constructors

constructor Create();

Config Settings (REST Component)

REST Config Settings

"value\ntest"

cookies & cream

value\ntest

cookies & cream

"value
test"

value
test

cookies & cream

HTTP Config Settings

TCPClient Config Settings

SSL Config Settings

-----BEGIN CERTIFICATE-----
MIIEKzCCAxOgAwIBAgIRANTET4LIkxdH6P+CFIiHvTowDQYJKoZIhvcNAQELBQAw
...
eWHV5OW1K53o/atv59sOiW5K3crjFhsBOd5Q+cJJnU+SWinPKtANXMht+EDvYY2w
F0I1XhM+pKj7FjDr+XNj
-----END CERTIFICATE-----
\r \n
-----BEGIN CERTIFICATE-----
MIIEFjCCAv6gAwIBAgIQetu1SMxpnENAnnOz1P+PtTANBgkqhkiG9w0BAQUFADBp
..
d8q23djXZbVYiIfE9ebr4g3152BlVCHZ2GyPdjhIuLeH21VbT/dyEHHA
-----END CERTIFICATE-----

-----BEGIN CERTIFICATE-----
MIIEKzCCAxOgAwIBAgIRANTET4LIkxdH6P+CFIiHvTowDQYJKoZIhvcNAQELBQAw
...
eWHV5OW1K53o/atv59sOiW5K3crjFhsBOd5Q+cJJnU+SWinPKtANXMht+EDvYY2w
F0I1XhM+pKj7FjDr+XNj
-----END CERTIFICATE-----
\r \n
-----BEGIN CERTIFICATE-----
MIIEFjCCAv6gAwIBAgIQetu1SMxpnENAnnOz1P+PtTANBgkqhkiG9w0BAQUFADBp
..
d8q23djXZbVYiIfE9ebr4g3152BlVCHZ2GyPdjhIuLeH21VbT/dyEHHA
-----END CERTIFICATE-----

Socket Config Settings

Base Config Settings

Trappable Errors (REST Component)

WebForm Errors

The component may also return one of the following error codes, which are inherited from other components.

MIME Errors

HTTP Errors

The component may also return one of the following error codes, which are inherited from other components.

TCPClient Errors

SSL Errors

TCP/IP Errors

XML Errors