MIME Class

Properties   Methods   Events   Config Settings   Errors  

The MIME class allows for the simple encoding and decoding of MIME structures, such as message attachments and file uploads.

Syntax

ipworkssmime.mime()

Remarks

The class may be used for decoding or encoding of messages. Message holds the content of the encoded message or the filename that holds the encoded data. The decoded data are provided in Parts properties.

To decode a MIME message, you should first assign either the whole message (headers and body) to Message or put the message headers into the MessageHeaders property and the message body or the filename holding it into the Message property. Calling DecodeFromFile or DecodeFromString directs the class to start parsing the message: it will fill out the ContentType and ContentTypeAttr properties with message content-type information, and it will enter information about message parts into the Parts properties, which includes part sizes, part content types, part content type attributes, part content disposition, part content disposition attributes, part encoding, part name, part filename, part headers, or part content (part-decoded string or part-decoded file) for each decoded part.

Calling the DecodeFromString or DecodeFromFile to decode does not actually decode the message but only parses it. The real decoding is done when the part content in the Parts properties is first accessed.

To encode data into a MIME message, you should first assign values for each part to either a part-decoded string or a part- decoded file in the Parts properties property, and optionally assign values to the other part attributes in the Parts properties. Assigning a value to the part-decoded string or a part-decoded file through the Parts properties, fills out automatically the part headers into the Parts properties for the respective part. Calling EncodeToFile or EncodeToString directs the class to fill out the Message with the message body and the MessageHeaders with the headers.

The Progress event is fired as the message is parsed and the data are decoded/encoded.

Property List

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

Method List

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

Event List

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

Config Settings

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

MIME.Boundary Property

This property includes the boundary separating the MIME parts. It has a maximum length of 80 bytes.

Syntax

getBoundary(): string;
setBoundary(boundary: string): void;

Default Value

""

Remarks

This property contains the boundary separating the MIME parts and has a maximum length of 80 bytes. The class automatically generates a random boundary value during encoding, if no value is given. During decoding, this property is filled with the boundary from the actual MIME message.

The class will truncate any string longer than 80 bytes if assigned to Boundary.

MIME.ContentType Property

This property includes the value of the content-type header of the message that was encoded/decoded.

Syntax

getContentType(): string;
setContentType(contentType: string): void;

Default Value

""

Remarks

This property contains the value of the content-type header of the message that was encoded/decoded. The class filters it out from the MessageHeaders. It shows the user information about the type of the parts and their relation to each other.

The content-type attributes, such as filename, boundary, and charset, are held in this property.

MIME.ContentTypeAttr Property

This property includes the attributes of the content-type header of the message that was encoded or decoded.

Syntax

getContentTypeAttr(): string;
setContentTypeAttr(contentTypeAttr: string): void;

Default Value

""

Remarks

This property contains content-type attributes such as "filename", "boundary", and "charset".

MIME.Message Property

This property contains the encoded message text or a path to a file that contains the encoded message text.

Syntax

getMessage(): Uint8Array;
setMessage(message: Uint8Array): void;

Default Value

""

Remarks

This property contains the encoded message text or a path to a file that contains the encoded message text. The class fills out this property with the message body and MessageHeaders during encoding. The user may assign both the headers and the body to this property and leave MessageHeaders empty before decoding.

This property is not available at design time.

MIME.MessageHeaders Property

This property includes the headers of the MIME message.

Syntax

getMessageHeaders(): HeaderList;
setMessageHeaders(messageHeaders: HeaderList): void;

Default Value

Remarks

This property contains the headers of the MIME message. The class fills out this property upon encoding. The user should use them as additional headers when emailing the Message.

During decoding, if this property is empty, the class will try to find the headers in the beginning of the Message and then will fill out this property accordingly.

Please refer to the Header type for a complete list of fields.

MIME.MessageHeadersString Property

This property includes the string version of the MIME message headers.

Syntax

getMessageHeadersString(): string;
setMessageHeadersString(messageHeadersString: string): void;

Default Value

""

Remarks

The component fills out MessageHeadersString upon encoding. The user should use these strings as additional headers when emailing the Message.

This property contains a string version of the MIME message headers. During decoding, if this property is empty, the class will try to find the headers in the beginning of the Message and will fill out this property accordingly.

MIME.Parts Property

This property contains information about all parts of a MIME message.

Syntax

getParts(): MIMEPartList;
setParts(parts: MIMEPartList): void;

Default Value

Remarks

This property contains information about all parts of a MIME message. A MIME message consists of different parts, separated by either a user-specified or an auto-generated boundary. Each part has its own set of headers that are contained in the field.

The MIMEPARTS collection is filled out by the class when a call to either DecodeFromFile or DecodeFromString is made. However, when the EncodeToFile or EncodeToString methods are called, the class encodes the data given in either or into a MIME message.

Please refer to the MIMEPart type for a complete list of fields.

MIME.config Method

Sets or retrieves a configuration setting.

Syntax

async mime.config(configurationString : string): Promise<string>

Remarks

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

These settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the class, 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.

MIME.decodeFromFile Method

This method decodes from a file.

Syntax

async mime.decodeFromFile(): Promise<void>

Remarks

This method decodes the data file given in Message and optionally MessageHeaders and fills out the Parts properties for each decoded part.

Example. Decoding from a File:

MIMEControl.Message = "C:\filename.txt" MIMEControl.DecodeFromFile

In this example, C:\filename.txt must contain the MIME headers and body. If not, the MessageHeaders property must be set to the appropriate MIME headers.

MIME.decodeFromString Method

This method decodes from a string.

Syntax

async mime.decodeFromString(): Promise<void>

Remarks

This method decodes from a string. It is the same as DecodeFromFile, but now the Message denotes the real encoded message rather than a filename.

This method decodes the data given in Message and optionally MessageHeaders and fills out the Parts properties.

Example. Decoding a Mail Message:

MIMEControl.MessageHeadersString = MailControl.MessageHeaders MIMEControl.Message = MailControl.MessageText MIMEControl.DecodeFromString

MIME.decodePart Method

This method decodes the specified part.

Syntax

async mime.decodePart(index : number): Promise<Uint8Array>

Remarks

This method decodes the part specified by Index and returns the decoded part data.

DecodeFromString or DecodeFromFile must be called before calling this method. Calling this method will return the decoded bytes, and in addition, the PartsDecodedString property will be populated with the string representation of the decoded data.

Example. Decoding a Specified Part:mime.MessageHeadersString = myMessageHeaders; mime.Message = myMessageBody; mime.DecodeFromString(); byte[] myPartContent = await mime.DecodePart(0);

MIME.decodePartToFile Method

This method decodes the specified part to a file on disk.

Syntax

async mime.decodePartToFile(index : number): Promise<string>

Remarks

This method decodes the part specified by Index to a temporary file. The full path to the temporary file is returned by this method. The user is responsible for deleting the temporary file.

DecodeFromString or DecodeFromFile must be called before calling this method.

MIME.encodeToFile Method

This method encodes to a file.

Syntax

async mime.encodeToFile(): Promise<void>

Remarks

This method encodes the data given in Parts properties (either a decoded file or a decoded string) into a MIME message at Message and MessageHeaders using the values optionally given in Parts properties. To encode several objects into a MIME envelope, the user should first clear any old values left in the Parts properties.

The class will check for each item in Parts properties (first the decoded file and then the decoded string) for the data to encode.

The encoded message will be saved in the file pointed to by Message; the message headers will be held by MessageHeaders.

Example. Encoding Data:

MIMEControl.ResetData() MIMEControl.PartCount = 2 MIMEControl.PartDecodedString(0) = "This is plain text data" MIMEControl.PartEncoding(0) = peQuotedPrintable MIMEControl.PartContentType(0) = "text/plain" MIMEControl.PartDecodedFile(1) = "C:\filename.txt" MIMEControl.Message = "temp.tmp" MIMEControl.EncodeToFile()

MIME.encodeToString Method

This method encodes to a string.

Syntax

async mime.encodeToString(): Promise<void>

Remarks

This method encodes to a string. It is the same as EncodeToFile but the encoded data are held in the Message property rather than saved to a file.

This method encodes the data given in the Parts properties into a MIME message. The message gets stored in Message and MessageHeaders using the values optionally given in Parts properties. To encode several objects into a MIME envelope, the user should first clear any old values left in the Parts properties by calling ResetData.

The class will check each item in the Parts properties (first the decoded file and then the decoded string) for the data to encode.

The encoded message will be stored in the Message property; the message headers will be held by MessageHeaders.

Example. Encoding Data:

MIMEControl.ResetData() MIMEControl.PartCount = 2 MIMEControl.PartDecodedString(0) = "This is plain text data" MIMEControl.PartEncoding(0) = peQuotedPrintable MIMEControl.PartContentType(0) = "text/plain" MIMEControl.PartDecodedFile(1) = "C:\filename.txt" MIMEControl.EncodeToString()

MIME.reset Method

Reset the class.

Syntax

async mime.reset(): Promise<void>

Remarks

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

MIME.resetData Method

This method resets the values of all headers and part properties.

Syntax

async mime.resetData(): Promise<void>

Remarks

This method resets the values of all headers and part properties. It is an easy way to reset the class's properties before starting to populate the part properties with new values.

MIME.Error Event

Information about errors during data delivery.

Syntax

mime.on('Error', listener: (e: {readonly errorCode: number, readonly description: string}) => void )

Remarks

The Error event is fired in case of exceptional conditions during message processing. Normally the class .

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.

MIME.Header Event

This event is fired every time a header is parsed.

Syntax

mime.on('Header', listener: (e: {readonly partIndex: number, readonly field: string, readonly value: string, readonly valueB: Uint8Array}) => void )

Remarks

The PartIndex parameter contains the index of the part containing the current header. If the header is from the MIME body, this value will be -1. The Field parameter contains the name of the MIME header. The Value parameter contains the header contents. The Header event is fired when a header is parsed, which occurs for each header of the message when DecodeFromFile, DecodeFromString, or DecodeFromStream is called.

MIME.Progress Event

This event shows the progress of decoding or encoding the input data.

Syntax

mime.on('Progress', listener: (e: {readonly percentDone: number}) => void )

Remarks

The Progress allows the user to visualize the progress of processing the input data.

The PercentDone parameter shows what percentage of the input has been read.

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 , and its corresponding .

Fields

Constructors

public Header();

public Header(String field, String value);

MIMEPart Type

This is a part of the MIME message.

Remarks

Each MIME message is split into parts. A message must have at least one part to be a valid MIME message. The message itself is split into the MessageHeaders and the Message body. The body is then split into MIME parts by a specified or generated Boundary. Each part of a MIME message has its own as well. These headers describe the MIMEPart and its contents.

The decoded data will be held in or otherwise will be saved in a temporary file given by when the user asks for the value of the respective field.

If the encoded data are file data, the decoded file(s) will be given in the field. Otherwise, the decoded data will be in the field.

When the EncodeToString method is called, the class will check for each item in the Parts properties (first the and then the ) for the data to encode.

Fields

Constructors

public MIMEPart();

public MIMEPart(String decodedFile);

public MIMEPart(byte[] decodedString);

Config Settings (class ipworkssmime.mime)

The class accepts one or more of the following configuration settings. Configuration settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the class, access to these internal properties is provided through the Config method.

MIME Config Settings

Base Config Settings

Trappable Errors (class ipworkssmime.mime)

MIME Errors

	3   Can't create the file for write (illegal name or disk is write-protected).
	4   Can't open the file for read (doesn't exist?).
	5   Can't read from file.
	6   Can't write to file (disk full?).
	280   Invalid Part Index.
	281   Unknown MIME type.
	282   No MIME-boundary found.
	283   No file given.
	284   The class is busy.
	285   Can't create a temporary file to decode the data.
	286   Can't read Message file.
	287   No header separator found.
	289   No separator found.
	290   Input stream must have seeking enabled.