NNTP Component

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The NNTP Component is used to read, search, and post articles on Usenet news servers.

Syntax

TipwNNTP

Remarks

The NNTP Component supports both plaintext and 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 NNTP Component implements a standard Usenet news reader as specified in RFC 977. It can be used to browse Usenet news groups and to read and post articles.

The CurrentGroup property sets the current newsgroup. From then on, news articles from that group can be read by setting the article number in CurrentArticle and then calling the appropriate method. Properties, such as ArticleCount, FirstArticle, and LastArticle, provide information about the current state.

The headers and text of the articles are received through the Header and Transfer events, respectively. Additionally, up to MaxLines from the article body are provided in the ArticleText property. The GroupOverview event returns information about a range of articles (OverviewRange) in CurrentGroup, and the GroupList event is used when listing newsgroup names. The PITrail event provides a trace of the interaction with the server.

The component supports posting of articles through the ArticleText and AttachedFile properties. The article text is specified in one or both of the above, and then the PostArticle method is called. Article headers are given in a series of properties, such as ArticleFrom, ArticleSubject, and Organization, that map directly to the Usenet article header with the same name.

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.

ArticleCount Property (NNTP Component)

This property includes the estimated number of articles in CurrentGroup .

Syntax

property ArticleCount: Int64 read get_ArticleCount;

Default Value

0

Remarks

This property contains the estimated number of articles in CurrentGroup. The value of this property is 0 if there is no current group (CurrentGroup is ''). Otherwise, when CurrentGroup is set, it is the number of articles in the group as shown by the news server. For most news servers, this is an estimated value of the number of the articles, rather than the exact value.

This property is read-only.

ArticleDate Property (NNTP Component)

This property includes the date of the current article.

Syntax

property ArticleDate: String read get_ArticleDate;

Default Value

''

Remarks

This property contains the date of the current article. If the component is not connected or CurrentArticle is empty, the value of this property is an empty string. Otherwise, it contains the date of the article as reported by the server. The NewsServer is asked about the headers of the article only if the CurrentArticle property has changed. If CurrentArticle has not changed, the component returns a cached value.

This property is read-only.

ArticleFrom Property (NNTP Component)

This property includes the email address of the author (for posting articles).

Syntax

property ArticleFrom: String read get_ArticleFrom write set_ArticleFrom;

Default Value

''

Remarks

This property contains the email address of the author (for posting articles). The string in this property is posted with a From article header to the news server.

If the resulting header is longer than MaxHeaderLength, then it is folded according to RFC 850 specifications.

This property is not available at design time.

ArticleHeaders Property (NNTP Component)

This property includes the full headers of the article as retrieved from the server.

Syntax

property ArticleHeaders: String read get_ArticleHeaders;

Default Value

''

Remarks

This property contains the full headers of the article as retrieved from the server. If the component is not connected or the CurrentArticle is empty, the value of this property is an empty string. Otherwise, it contains the full headers of the article as reported by the server.

The NewsServer is asked about the headers of the article only if the CurrentArticle property has changed. If CurrentArticle has not changed, the component returns a cached value.

This property is read-only.

ArticleId Property (NNTP Component)

This property includes the message identifier of the current article.

Syntax

property ArticleId: String read get_ArticleId;

Default Value

''

Remarks

This property contains the message identifier of the current article. If the component is not connected or the CurrentArticle is empty, the value of this property is an empty string. Otherwise, it contains the message identifier of the article as reported by the server. The NewsServer is asked about the headers of the article only if the CurrentArticle property has changed. If the CurrentArticle has not changed, the component returns a cached value.

This property is read-only.

ArticleList Property (NNTP Component)

This property includes a collection of articles collected through GroupOverview or GroupSearch .

Syntax

property ArticleList: TipwArticleInfoList read get_ArticleList;

Remarks

This property contains a collection of articles collected through GroupOverview or GroupSearch. This collection consists of a list of ArticleInfo objects. The returned list contains information about each article in the OverviewRange or SearchRange when either GroupOverview or GroupSearch is called.

ArticleInfoLimit can be used to control the number of articles saved.

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

ArticleReferences Property (NNTP Component)

This property includes articles to which the posted article follows up.

Syntax

property ArticleReferences: String read get_ArticleReferences write set_ArticleReferences;

Default Value

''

Remarks

This property contains articles to which the posted article follows up. If this property contains a nonempty string, a References article header is created for the article. This header shows the article identifiers for the posted article to which it refers.

The references must be separated by space characters.

If the resulting header is longer than MaxHeaderLength, then it is folded according to RFC 850 specifications.

This property is not available at design time.

ArticleReplyTo Property (NNTP Component)

This property includes the address to reply to (for posting articles).

Syntax

property ArticleReplyTo: String read get_ArticleReplyTo write set_ArticleReplyTo;

Default Value

''

Remarks

This property contains the address to reply to (for posting articles). If this property contains a nonempty string, a Reply-To article header is created for the article. This header shows the address to use for replies, which is useful if this address is different from the one in ArticleFrom.

If the resulting header is longer than MaxHeaderLength, then it is folded according to RFC 850 specifications.

This property is not available at design time.

ArticleSubject Property (NNTP Component)

This property includes the article subject (for posted articles).

Syntax

property ArticleSubject: String read get_ArticleSubject write set_ArticleSubject;

Default Value

''

Remarks

The string in this property is posted with a Subject article header to the news server.

If the resulting header is longer than MaxHeaderLength, then it is folded according to RFC 850 specifications.

This property is not available at design time.

ArticleText Property (NNTP Component)

This property includes the full text of the article (without the headers).

Syntax

property ArticleText: String read get_ArticleText write set_ArticleText;

Default Value

''

Remarks

This property contains the full text of the article (without the headers). If the component is not connected or CurrentArticle is empty, the value of this property is an empty string. Otherwise, it contains the full text of the article as reported by the server.

The NewsServer is asked about the text of the article only if the CurrentArticle property has changed. If CurrentArticle has not changed, the component returns a cached value.

When posting articles, this property contains the full text of the article to post.

It is advisable that the text contained in this property be a collection of lines with lengths less than or equal to 80 bytes separated by CRLF ('#13#10') . The text in the article lines must contain 7-bit characters so that the article can be successfully transferred through the various Usenet news servers on the Internet.

The component automatically escapes lines that start with a '.' by adding another '.' as specified in RFC 977. The article text is unescaped by the news server, so the process is fully transparent.

This property is not available at design time.

AttachedFile Property (NNTP Component)

This property includes a filename for which the contents will be appended to the ArticleText when posting articles.

Syntax

property AttachedFile: String read get_AttachedFile write set_AttachedFile;

Default Value

''

Remarks

The content of this property is appended to the text in ArticleText (if any) and sent to the news server. This property is useful for posting arbitrarily large articles or sending MIME attachments.

It is advisable that the text contained in the file be a collection of lines with lengths less than or equal to 80 bytes separated by CRLF ('#13#10') . The text in the message lines must contain only 7-bit characters so that the message may be sent successfully through the various Usenet news servers on the Internet.

The component automatically escapes lines that start with a '.' by adding another as specified in RFC 822. The article text is unescaped by the news server, so the process is fully transparent.

This property is not available at design time.

CheckDate Property (NNTP Component)

This property includes the date (format YYMMDD HHMMSS) to check for the creation of new groups. If the group was created after the date specified, it is considered new.

Syntax

property CheckDate: String read get_CheckDate write set_CheckDate;

Default Value

'000101 000000'

Remarks

This property contains the date (format YYMMDD HHMMSS) to check for the creation of new groups. If the group was created after the date specified, it is considered new. The value of this property is used as an argument for the ListNewGroups method.

This property is not available at design time.

Command Property (NNTP Component)

This property is used to send additional commands directly to the server.

Syntax

property Command: String write set_Command;

Default Value

''

Remarks

This property can be used to send additional commands directly to the server. Check the LastReply property or trap the PITrail events coming from the server to get the response.

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

Connected Property (NNTP 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.

CurrentArticle Property (NNTP Component)

This property includes the number or message identifier of the current article.

Syntax

property CurrentArticle: String read get_CurrentArticle write set_CurrentArticle;

Default Value

''

Remarks

This property specifies either a message identifier or an article number uniquely identifying a particular article. It is then used as an argument to methods such as FetchArticle.

CurrentGroup Property (NNTP Component)

This property includes the name of the current group.

Syntax

property CurrentGroup: String read get_CurrentGroup write set_CurrentGroup;

Default Value

''

Remarks

This property contains the name of the current group. When this property is set to a valid group name, the component sends a Network News Transfer Protocol (NNTP) GROUP command to the NewsServer and enters the specified group. If the command is successful, FirstArticle, LastArticle, and ArticleCount are set to the reported values for the group. This property is then used for all references to articles (until it is changed to another group).

Note: It is recommended to use the ChangeCurrentGroup method instead of setting this property.

Firewall Property (NNTP 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.

FirstArticle Property (NNTP Component)

This property includes the number of the first article in CurrentGroup .

Syntax

property FirstArticle: Int64 read get_FirstArticle;

Default Value

0

Remarks

This property contains the number of the first article in CurrentGroup. The value of this property is zero if there is no current group (CurrentGroup is '').

This property is read-only.

GroupList Property (NNTP Component)

This property includes a collection of newsgroups listed by ListGroups or ListNewGroups .

Syntax

property GroupList: TipwGroupInfoList read get_GroupList;

Remarks

This property contains a collection of newsgroups listed by ListGroups or ListNewGroups. This collection consists of a list of GroupInfo objects. These objects contain information about each group such as the name, first and last article, and whether or not you can post to the group.

GroupInfoLimit can be used to control the number of groups saved.

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

Idle Property (NNTP 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.

LastArticle Property (NNTP Component)

This property includes the number of the last article in CurrentGroup .

Syntax

property LastArticle: Int64 read get_LastArticle;

Default Value

0

Remarks

This property contains the number of the last article in CurrentGroup. The value of this property is zero if there is no current group (CurrentGroup is '').

This property is read-only.

LastReply Property (NNTP Component)

The last reply from the server.

Syntax

property LastReply: String read get_LastReply;

Default Value

''

Remarks

This property indicates the last reply received from the server. It can be used for informational purposes. The same information and more can also be retrieved through the PITrail event.

This property is read-only.

LocalFile Property (NNTP Component)

This property includes the path to a local file to download the article body. If the file exists, it is overwritten (optional).

Syntax

property LocalFile: String read get_LocalFile write set_LocalFile;

Default Value

''

Remarks

This property is used when retrieving an article. If this property is empty, then the received data are provided through the parameters of the Transfer event.

LocalHost Property (NNTP 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.

MaxLines Property (NNTP Component)

This property includes the maximum number of message lines aside from headers to retrieve.

Syntax

property MaxLines: Int64 read get_MaxLines write set_MaxLines;

Default Value

0

Remarks

This property is used to limit the number of text lines aside from headers retrieved for messages. This property is used in conjunction with the ArticleText property.

Note: Because of the Network News Transfer Protocol (NNTP) limitations, the full text of the article is always retrieved from the server, but only MaxLines will be stored in ArticleText.

The default value of the property is zero. In this case, the entire message will be retrieved, without interruptions.

This property is not available at design time.

Newsgroups Property (NNTP Component)

This property includes a comma-separated list of newsgroups in which to post the article.

Syntax

property Newsgroups: String read get_Newsgroups write set_Newsgroups;

Default Value

''

Remarks

The string in this property is posted with a Newsgroups article header to the news server. It specifies the list of groups where the article is posted (comma separated).

If this property contains '' (empty string), then the value of the CurrentGroup property is used to specify the target newsgroup for the posted article.

If the resulting header is longer than MaxHeaderLength, then it is folded according to RFC 850 specifications.

This property is not available at design time.

NewsPort Property (NNTP Component)

This property includes the server port for the secure Network News Transfer Protocol (NNTP) (default 119).

Syntax

property NewsPort: Integer read get_NewsPort write set_NewsPort;

Default Value

119

Remarks

For implicit Secure Sockets Layer (SSL), use port 563 (please refer to the SSLStartMode property for more information).

A valid port number (a value between 1 and 65535) is required for the connection to take place. The property must be set before a connection is attempted and cannot be changed once a connection is established. Any attempt to change this property while connected will fail with an error.

This property is not available at design time.

NewsServer Property (NNTP Component)

This property includes the name or address of a news server.

Syntax

property NewsServer: String read get_NewsServer write set_NewsServer;

Default Value

''

Remarks

This property specifies the IP address (IP number in dotted internet format) or the domain name for the news server. It is set before a connection is attempted and cannot be changed once a connection is in progress.

If this property is set to a domain name, a DNS request is initiated. Upon successful termination of the request, this property is set to the corresponding address. If the search is not successful, an error is returned.

If the component is configured to use a SOCKS firewall, the value assigned to this property may be preceded with an "*". If this is the case, the host name is passed to the firewall unresolved and the firewall performs the DNS resolution.

Organization Property (NNTP Component)

This property includes the organization of the author (for posting articles).

Syntax

property Organization: String read get_Organization write set_Organization;

Default Value

''

Remarks

This property contains the organization of the article's author. If this property contains a nonempty string, an Organization article header is created for the article. This header shows the organization of the author and is used for information purposes only.

If the resulting header is longer than MaxHeaderLength, then it is folded according to RFC 850 specifications.

This property is not available at design time.

OtherHeaders Property (NNTP Component)

This property includes an RFC 850-compliant string consisting of extra headers (for posting articles).

Syntax

property OtherHeaders: String read get_OtherHeaders write set_OtherHeaders;

Default Value

''

Remarks

This property contains a string of headers to be appended to the message headers created from other properties like From and Subject.

The headers must be of the format "header: value" as specified in RFC 850. Header lines should be separated by CRLF ('#13#10') .

Use this property with caution. If this property contains invalid headers, article posting might not be successful.

This property is useful for extending the functionality of the component. A good example is posting of MIME attachments.

Special Case: If this property starts with an empty line (e.g., carriage return line feed, CRLF), then the value of this property is used instead of the normally computed article headers.

This property is not available at design time.

OverviewRange Property (NNTP Component)

This property includes the range for the GroupOverview method (first-last).

Syntax

property OverviewRange: String read get_OverviewRange write set_OverviewRange;

Default Value

'-'

Remarks

This property specifies a range of articles for which to retrieve article overviews from the server. The format is 'first-last' where first is '' (empty string) or a positive number, and last is '' (empty string), a positive number, or the token end.

The default value of this property is '-', meaning 'all articles in the group'.

This property is not available at design time.

ParsedHeaders Property (NNTP Component)

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

Syntax

property ParsedHeaders: TipwHeaderList read get_ParsedHeaders;

Remarks

This property contains a collection of headers returned from the last article retrieval. This property is populated when either FetchArticle or FetchArticleHeaders is called. It contains a list of all of the headers from the article fetched.

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

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

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

Password Property (NNTP Component)

This property includes the logon password for the NewsServer .

Syntax

property Password: String read get_Password write set_Password;

Default Value

''

Remarks

This property contains a logon password for the NewsServer. If this property is set to a nonempty string, then when connecting to the NewsServer an AUTHINFO PASS command is sent to provide authentication information for the user. This command is not part of the Network News Transfer Protocol (NNTP), but it is widely used by popular news servers.

SearchHeader Property (NNTP Component)

This property includes a header for the GroupSearch method.

Syntax

property SearchHeader: String read get_SearchHeader write set_SearchHeader;

Default Value

''

Remarks

This property specifies the header to search for SearchPattern (e.g., Subject).

This property is not available at design time.

SearchPattern Property (NNTP Component)

This property includes a search pattern for the GroupSearch method.

Syntax

property SearchPattern: String read get_SearchPattern write set_SearchPattern;

Default Value

''

Remarks

This property contains a search pattern for the GroupSearch method. The format of the pattern is the same as the patterns used by the UNIX Find command.

As an example, "* new *" will match all headers that contain the word "new".

This property is not available at design time.

SearchRange Property (NNTP Component)

This property includes the range for the GroupSearch method (first-last).

Syntax

property SearchRange: String read get_SearchRange write set_SearchRange;

Default Value

'-'

Remarks

This property specifies a range of articles for which to do a search on the server. The format is First-Last where First is '' (empty string) or a positive number, and Last is '' (empty string), a positive number, or the token End.

The default value of the property is "-", meaning "search all articles in the group".

This property is not available at design time.

SSLAcceptServerCertEncoded Property (NNTP 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 (NNTP 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 (NNTP 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 (NNTP 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 (NNTP 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 (NNTP 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.

SSLEnabled Property (NNTP Component)

Whether TLS/SSL is enabled.

Syntax

property SSLEnabled: Boolean read get_SSLEnabled write set_SSLEnabled;

Default Value

false

Remarks

This setting specifies whether TLS/SSL is enabled in the component. When False (default) the component operates in plaintext mode. When True TLS/SSL is enabled.

TLS/SSL may also be enabled by setting SSLStartMode. Setting SSLStartMode will automatically update this property value.

This property is not available at design time.

SSLProvider Property (NNTP 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 (NNTP 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.

SSLStartMode Property (NNTP Component)

Determines how the component starts the SSL negotiation.

Syntax

property SSLStartMode: TipwTSSLStartModes read get_SSLStartMode write set_SSLStartMode;

TipwTSSLStartModes = (
  sslAutomatic,
  sslImplicit,
  sslExplicit,
  sslNone
);

Default Value

sslNone

Remarks

The SSLStartMode property may have one of the following values:

Timeout Property (NNTP 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.

User Property (NNTP Component)

This property includes a user identifier to login as in the NewsServer .

Syntax

property User: String read get_User write set_User;

Default Value

''

Remarks

This property contains a user identifier to login as in the NewsServer. If this property is set to a nonempty string, then when connecting to the NewsServer an AUTHINFO USER command is sent to provide authentication information for the user. Although this command is not part of the Network News Transfer Protocol (NNTP), it is widely used by news servers for authentication purposes.

ChangeCurrentGroup Method (NNTP Component)

This method changes the current group.

Syntax

procedure ChangeCurrentGroup(Group: String);

Remarks

This method changes the current group. When calling this method, the component sends a Network News Transfer Protocol (NNTP) GROUP command to the NewsServer and enters the specified group. If the command is successful, FirstArticle, LastArticle, and ArticleCount are set to the reported values for the group.

Config Method (NNTP 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.

Connect Method (NNTP Component)

This method connects to the news server.

Syntax

procedure Connect();

Remarks

This method is used to connect to the news server. If the User and/or Password are set, then corresponding AUTHINFO commands are sent to the NewsServer as well.

Disconnect Method (NNTP Component)

This method disconnects from the news server.

Syntax

procedure Disconnect();

Remarks

This method is used to disconnect from the NewsServer. The component first attempts to send a QUIT command, and if that fails, the connection is broken.

DoEvents Method (NNTP 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.

FetchArticle Method (NNTP Component)

This method gets the headers and body of an article specified in CurrentArticle .

Syntax

procedure FetchArticle();

Remarks

This method gets the headers and body of the article specified in CurrentArticle. The headers are delivered through the Header event, and the article body is delivered through the Transfer event.

If a connection to the NewsServer does not already exist, a new one is created.

FetchArticleBody Method (NNTP Component)

This method gets only the body of an article specified in CurrentArticle .

Syntax

procedure FetchArticleBody();

Remarks

This method gets only the body of the article specified in CurrentArticle. The body is delivered through the Transfer event.

If a connection to the NewsServer does not already exist, a new one is created.

FetchArticleHeaders Method (NNTP Component)

This method gets only the headers of an article specified in CurrentArticle .

Syntax

procedure FetchArticleHeaders();

Remarks

This method gets only the headers of the article specified in CurrentArticle. The headers are delivered through the Header event.

If a connection to the NewsServer does not already exist, a new one is created.

GroupOverview Method (NNTP Component)

This method receives an overview for the articles in range OverviewRange in the CurrentGroup .

Syntax

procedure GroupOverview();

Remarks

This method receives an overview for the articles in range OverviewRange in the CurrentGroup. The overview data are delivered through the GroupOverview event.

If a connection to the NewsServer does not already exist, a new one is created.

GroupSearch Method (NNTP Component)

This method receives an overview for the articles in the range SearchRange in the CurrentGroup .

Syntax

procedure GroupSearch();

Remarks

This method searches the current newsgroup for articles in the range SearchRange in the CurrentGroup, where SearchHeader matches SearchPattern. The results are delivered through the GroupSearch event.

If a connection to the NewsServer does not already exist, a new one is created.

Interrupt Method (NNTP Component)

Interrupt the current method.

Syntax

procedure Interrupt();

Remarks

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

ListGroups Method (NNTP Component)

This method lists all newsgroups on the server.

Syntax

procedure ListGroups();

Remarks

This method asks the server to list all of its newsgroups. Use this method with caution as listing groups may take quite a long time over slow links. The group names and other information are returned via the GroupList event.

If a connection to the NewsServer does not already exist, a new one is created.

ListNewGroups Method (NNTP Component)

This method lists all newgroups on the server.

Syntax

procedure ListNewGroups();

Remarks

This method asks the server to list all of the newsgroups created since CheckDate. The group names (if any) and other information are returned via the GroupList event.

If a connection to the NewsServer does not already exist, a new one is created.

LocalizeDate Method (NNTP Component)

This method converts a valid RFC 822 message date to a local date and time.

Syntax

function LocalizeDate(DateTime: String): String;

Remarks

This method can be used to convert an RFC 822 date and time string to the corresponding local date and time.

Note: Dates will be returned in the format: "MM/dd/yyyy hh:mm:ss".

PostArticle Method (NNTP Component)

This method posts the current article and attached file.

Syntax

procedure PostArticle();

Remarks

This method posts the current article and attached file (if any). If a connection to the NewsServer does not already exist, a new one is created.

Reset Method (NNTP Component)

This method resets the component.

Syntax

procedure Reset();

Remarks

This method will reset the component's properties to their default values.

ResetHeaders Method (NNTP Component)

This method resets all of the article headers.

Syntax

procedure ResetHeaders();

Remarks

This method resets all the article headers to '' (empty string). Use this method before posting a new article, so that headers from the previous article are not carried over to the next one.

SendCommand Method (NNTP Component)

Sends the exact command directly to the server.

Syntax

procedure SendCommand(Command: String);

Remarks

This method sends the command specified by Command to the server exactly as it is provided. Use this method to send additional or custom commands directly to the server.

After calling this method check the LastReply property and/or monitor the PITrail event to obtain the server's response.

ConnectionStatus Event (NNTP 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:

EndTransfer Event (NNTP Component)

This event is fired when the article text completes transferring.

Syntax

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

property OnEndTransfer: TEndTransferEvent read FOnEndTransfer write FOnEndTransfer;

Remarks

The purpose of the EndTransfer event is twofold: (1) during article retrieval, it fires when the article body finishes transferring from the NewsServer to the local host; and (2) during article posting, it fires after the article body has been sent to the NewsServer.

If ArticleText is not empty, the EndTransfer event is fired when the ArticleText finishes transferring from the local host to the NewsServer. If ArticleText is empty, the event is not fired.

If a file is attached to the ArticleText through the AttachedFile property, then EndTransfer fires again when the file finishes transferring. Please see the description of the AttachedFile property for more information.

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

Error Event (NNTP 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.

GroupList Event (NNTP Component)

This event is fired while group data transfers (during group listings).

Syntax

type TGroupListEvent = procedure (
  Sender: TObject;
  const Group: String;
  FirstArticle: Int64;
  LastArticle: Int64;
  CanPost: Boolean
) of Object;

property OnGroupList: TGroupListEvent read FOnGroupList write FOnGroupList;

Remarks

The GroupList event is fired for every group reported by the NewsServer when the ListGroups or ListNewGroups method is called.

The Group parameter shows the name of the group.

The FirstArticle and LastArticle parameters contain the article numbers for the first and last articles in the group.

The CanPost is True or False depending on whether article posting is allowed in the group specified by Group.

GroupOverview Event (NNTP Component)

This event is fired for each line of article overview data (during group overviews).

Syntax

type TGroupOverviewEvent = procedure (
  Sender: TObject;
  ArticleNumber: Int64;
  const Subject: String;
  const From: String;
  const ArticleDate: String;
  const MessageId: String;
  const References: String;
  ArticleSize: Int64;
  ArticleLines: Int64;
  const OtherHeaders: String
) of Object;

property OnGroupOverview: TGroupOverviewEvent read FOnGroupOverview write FOnGroupOverview;

Remarks

ArticleNumber contains the number of the article within the group.

Subject contains the subject of the article.

From contains the email address of the article author.

ArticleDate contains the date the article was posted.

MessageId contains the unique message Id for the article.

References contains the message Ids for the articles this article refers to (separated by spaces).

ArticleSize contains the size of the article in bytes.

ArticleLines contains the number of lines in the article.

OtherHeaders contains any other article headers that NewsServer chooses to display for the article.

GroupSearch Event (NNTP Component)

This event is fired for each line of group search data (during group searches).

Syntax

type TGroupSearchEvent = procedure (
  Sender: TObject;
  ArticleNumber: Int64;
  const Header: String
) of Object;

property OnGroupSearch: TGroupSearchEvent read FOnGroupSearch write FOnGroupSearch;

Remarks

ArticleNumber contains the number of the article within the group.

Header contains the matching header.

Header Event (NNTP Component)

This event is fired for every article header being retrieved during article retrieval.

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 header (In the same case 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).

PITrail Event (NNTP Component)

This event traces the commands sent to the news server, and the respective replies.

Syntax

type TPITrailEvent = procedure (
  Sender: TObject;
  Direction: Integer;
  const Message: String
) of Object;

property OnPITrail: TPITrailEvent read FOnPITrail write FOnPITrail;

Remarks

The PITrail event is useful for debugging purposes. It shows all the interaction between the client and the server, line by line, except for group listings, group overviews, article header, and article body transfers.

The Message parameter contains the full text of the message. The Direction parameter shows the originator of the message:

SSLServerAuthentication Event (NNTP 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 (NNTP 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.

StartTransfer Event (NNTP Component)

This event is fired when the article text starts transferring.

Syntax

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

property OnStartTransfer: TStartTransferEvent read FOnStartTransfer write FOnStartTransfer;

Remarks

The purpose of the StartTransfer event is twofold: during article retrieval, it fires when the article body starts transferring from the NewsServer to the local host, and during article posting, it fires before the article body is sent to the NewsServer.

If ArticleText is not empty, the StartTransfer event is fired when the ArticleText starts transferring from the local host to the NewsServer. If ArticleText is empty, the event is not fired.

If a file is attached to the ArticleText via the AttachedFile property, then StartTransfer fires again when the file starts transferring. Please go to the description of the AttachedFile property for more information.

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

Transfer Event (NNTP Component)

This event is fired while the article text gets transferred (to or from the NewsServer ).

Syntax

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

property OnTransfer: TTransferEvent read FOnTransfer write FOnTransfer;

Remarks

One or more Transfer events are fired during article retrieval. The Text parameter contains the portion of article data being retrieved.

The BytesTransferred parameter contains the number of bytes transferred since the beginning of the article, including header bytes.

One or more Transfer events are also fired during article posting. Articles consist of ArticleText and an optional AttachedFile. The BytesTransferred parameter shows the number of bytes sent starting from the beginning of ArticleText and/or AttachedFile.

The Transfer event is fired for every line of the article. For complete lines, there is no terminating newline at the end of the Text parameter, and EOL is True. The EOL parameter is False when a line is broken (usually for being too long).

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.

ArticleInfo Type

This is an article listed as a result of a GroupOverview or GroupSearch .

Remarks

This type describes information about an article as returned by the server after a GroupOverview or GroupSearch. It includes fields to denote detailed information about the article.

Fields

Constructors

constructor Create();

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();

GroupInfo Type

This is a group listed by the Network News Transfer Protocol (NNTP) server.

Remarks

This type describes information about a group as returned by the server. The GroupInfo fields contain information about each group, such as the name, first and last article, and whether or not you can post to the group.

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);

Config Settings (NNTP Component)

NNTP 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 (NNTP Component)

NNTP 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