nsIMIMEHeaderParam

IID:ddbbdfb8-a1c0-4dd5-a31b-5d2a7a3bb6ec
Inherits From:nsISupports

This interface is implemented by the following components:


Methods

[noscript] ACString decodeParameter ( ACString paramValue , char* charset , char* defaultCharset , PRBool overrideCharset ) [noscript] ACString decodeRFC2047Header ( char* headerVal , char* defaultCharset , PRBool overrideCharset , PRBool eatContinuation ) AString getParameter ( ACString headerVal , char* paramName , ACString fallbackCharset , PRBool tryLocaleCharset , out char* lang ) [noscript] char* getParameterInternal ( char* headerVal , char* paramName , out char* charset , out char* lang )

ACString decodeParameter ( ACString paramValue , char* charset , char* defaultCharset , PRBool overrideCharset )

Given a header parameter, decodes RFC 2047 style encoding (if it's not obtained from RFC 2231 encoding), converts it to UTF-8 and returns the result in UTF-8 if an attempt to extract charset info. from a few different sources succeeds. Otherwise, returns the input header value (in whatever encoding) as it is except that RFC 822 (using backslash) quotation is stripped off.

For internal use only. The only other place where this needs to be invoked is mime_decode_filename in mailnews/mime/src/mimehdrs.cpp defined as char * mime_decode_filename(char *name, const char *charset, MimeDisplayOptions *opt)

Arguments:
paramValue: the value of a parameter to decode and convert
charset: charset obtained from RFC 2231 decoding in which aParamValue is encoded. If null, indicates that it needs to try RFC 2047, instead.
defaultCharset: MIME charset to use when charset is null and cannot be obtained per RFC 2047 (most likely because 'bare' string is used.) Besides, it overrides charset/MIME charset obtained from RFC 2047 if aOverrideCharset is set.
overrideCharset: When set, overrides MIME charset specified in RFC 2047 style encoding with aDefaultCharset
Returns:
decoded parameter

ACString decodeRFC2047Header ( char* headerVal , char* defaultCharset , PRBool overrideCharset , PRBool eatContinuation )

Given a header value, decodes RFC 2047-style encoding and returns the decoded header value in UTF-8 if either it's RFC-2047-encoded or defaultCharset is given. Otherwise, returns the input header value (in whatever encoding) as it is except that RFC 822 (using backslash) quotation and CRLF (if eatContinuation is set) are stripped away

For internal use only. The only other place where this needs to be invoked is MIME_DecodeMimeHeader in mailnews/mime/src/mimehdrs.cpp defined as char * Mime_DecodeMimeHeader(char *header_val, const char *charset, PRBool override, PRBool eatcontinuation)

Arguments:
headerVal: a header value to decode
defaultCharset: MIME charset to use in place of MIME charset specified in RFC 2047 style encoding when aOverrideCharset is set.
overrideCharset: When set, overrides MIME charset specified in RFC 2047 style encoding with aDefaultCharset
eatContinuation: When set, removes CR/LF
Returns:
decoded header value

AString getParameter ( ACString headerVal , char* paramName , ACString fallbackCharset , PRBool tryLocaleCharset , out char* lang )

Given the value of a single header field (such as Content-Disposition and Content-Type) and the name of a parameter (e.g. filename, name, charset), returns the value of the parameter. The value is obtained by decoding RFC 2231-style encoding, RFC 2047-style encoding, and converting to UniChar(UTF-16) from charset specified in RFC 2231/2047 encoding, UTF-8, aFallbackCharset and the locale charset as the last resort if TryLocaleCharset is set.

This method internally invokes getParameterInternal, However, it does not stop at decoding RFC 2231 (the task for getParameterInternal but tries to cope with several non-standard-compliant cases mentioned below.

Note that a lot of MUAs and HTTP servers put RFC 2047-encoded parameters in mail headers and HTTP headers. Unfortunately, this includes Mozilla as of 2003-05-30. Even more standard-ignorant MUAs, web servers and application servers put 'raw 8bit characters'. This will try to cope with all these cases as gracefully as possible. Additionally, it returns the language tag if the parameter is encoded per RFC 2231 and includes lang.

Arguments:
headerVal: a header string to get the value of a parameter from.
paramName: the name of a MIME header parameter (e.g. filename, name, charset). If empty, returns the first (possibly) _unnamed_ 'parameter'.
fallbackCharset: fallback charset to try if the string after RFC 2231/2047 decoding or the raw 8bit string is not UTF-8
tryLocaleCharset: If set, makes yet another attempt with the locale charset.
lang: If non-null, assigns it to a pointer to a string containing the value of language obtained from RFC 2231 parsing. Caller has to nsMemory::Free it.
Returns:
the value of aParamName in Unichar(UTF-16).

char* getParameterInternal ( char* headerVal , char* paramName , out char* charset , out char* lang )

Given the value of a single header field (such as Content-Disposition and Content-Type) and the name of a parameter (e.g. filename, name, charset), returns the value of the parameter after decoding RFC 2231-style encoding.

For internal use only. The only other place where this needs to be invoked is MimeHeaders_get_parameter in mailnews/mime/src/mimehdrs.cpp defined as char * MimeHeaders_get_parameter (const char *header_value, const char *parm_name, char **charset, char **language)

Otherwise, this method would have been made static.

Arguments:
headerVal: a header string to get the value of a parameter from.
paramName: the name of a MIME header parameter (e.g. filename, name, charset). If empty, returns the first (possibly) _unnamed_ 'parameter'.
charset: If non-null, it gets assigned a new pointer to a string containing the value of charset obtained from RFC 2231 parsing. Caller has to nsMemory::Free it.
lang: If non-null, it gets assigned a new pointer to a string containing the value of language obtained from RFC 2231 parsing. Caller has to nsMemory::Free it.
Returns:
the value of aParamName after RFC 2231 decoding but without charset conversion.

Reference documentation is generated from Mozilla's source.

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