uri: library of generic URI related routines

## uri

uri - library of generic URI related routines

library of generic URI related routines Implements RFC 2396

Author(s): Daniel Veillard

## Synopsis

    typedef struct _xmlURI xmlURI;
    typedef xmlURI * xmlURIPtr;
    int	xmlNormalizeURIPath		(char * path);
    void	xmlPrintURI			(FILE * stream,
    					 xmlURIPtr uri);
    xmlURIPtr	xmlParseURIRaw		(const char * str,
    					 int raw);
    char *	xmlURIUnescapeString		(const char * str,
    					 int len,
    					 char * target);
    xmlURIPtr	xmlParseURI		(const char * str);
    xmlURIPtr	xmlCreateURI		(void);
    xmlChar *	xmlURIEscapeStr		(const xmlChar * str,
    					 const xmlChar * list);
    xmlChar *	xmlPathToURI		(const xmlChar * path);
    xmlChar *	xmlCanonicPath		(const xmlChar * path);
    void	xmlFreeURI			(xmlURIPtr uri);
    int	xmlParseURIReference		(xmlURIPtr uri,
    					 const char * str);
    xmlChar *	xmlBuildRelativeURI	(const xmlChar * URI,
    					 const xmlChar * base);
    xmlChar *	xmlSaveUri		(xmlURIPtr uri);
    xmlChar *	xmlURIEscape		(const xmlChar * str);
    xmlChar *	xmlBuildURI		(const xmlChar * URI,
    					 const xmlChar * base);

## Description

## Details

### Structure xmlURI

    struct _xmlURI {
        char *	scheme	: the URI scheme
        char *	opaque	: opaque part
        char *	authority	: the authority part
        char *	server	: the server part
        char *	user	: the user part
        int	port	: the port number
        char *	path	: the path string
        char *	query	: the query string (deprecated - use with caution)
        char *	fragment	: the fragment identifier
        int	cleanup	: parsing potentially unclean URI
        char *	query_raw	: the query string (as it appears in the URI)
    } xmlURI;

### Typedef xmlURIPtr

    xmlURI * xmlURIPtr;

### xmlBuildRelativeURI ()

    xmlChar *	xmlBuildRelativeURI	(const xmlChar * URI,
    					 const xmlChar * base)

Expresses the URI of the reference in terms relative to the base. Some examples of this operation include: base = "http://site1.com/docs/book1.html" URI input URI returned docs/pic1.gif pic1.gif docs/img/pic1.gif img/pic1.gif img/pic1.gif ../img/pic1.gif http://site1.com/docs/pic1.gif pic1.gif http://site2.com/docs/pic1.gif http://site2.com/docs/pic1.gif base = "docs/book1.html" URI input URI returned docs/pic1.gif pic1.gif docs/img/pic1.gif img/pic1.gif img/pic1.gif ../img/pic1.gif http://site1.com/docs/pic1.gif http://site1.com/docs/pic1.gif Note: if the URI reference is really weird or complicated, it may be worthwhile to first convert it into a "nice" one by calling xmlBuildURI (using 'base') before calling this routine, since this routine (for reasonable efficiency) assumes URI has already been through some validation.

`URI`: | the URI reference under consideration
`base`: | the base value
`Returns`: | a new URI string (to be freed by the caller) or NULL in case error.

### xmlBuildURI ()

    xmlChar *	xmlBuildURI		(const xmlChar * URI,
    					 const xmlChar * base)

Computes he final URI of the reference done by checking that the given URI is valid, and building the final URI using the base URI. This is processed according to section 5.2 of the RFC 2396 5.2. Resolving Relative References to Absolute Form

`URI`: | the URI instance found in the document
`base`: | the base value
`Returns`: | a new URI string (to be freed by the caller) or NULL in case of error.

### xmlCanonicPath ()

    xmlChar *	xmlCanonicPath		(const xmlChar * path)

Constructs a canonic path from the specified path.

`path`: | the resource locator in a filesystem notation
`Returns`: | a new canonic path, or a duplicate of the path parameter if the construction fails. The caller is responsible for freeing the memory occupied by the returned string. If there is insufficient memory available, or the argument is NULL, the function returns NULL.

### xmlCreateURI ()

    xmlURIPtr	xmlCreateURI		(void)

Simply creates an empty xmlURI

`Returns`: | the new structure or NULL in case of error

### xmlFreeURI ()

    void	xmlFreeURI			(xmlURIPtr uri)

Free up the xmlURI struct

`uri`: | pointer to an xmlURI

### xmlNormalizeURIPath ()

    int	xmlNormalizeURIPath		(char * path)

Applies the 5 normalization steps to a path string--that is, RFC 2396 Section 5.2, steps 6.c through 6.g. Normalization occurs directly on the string, no new allocation is done

`path`: | pointer to the path string
`Returns`: | 0 or an error code

### xmlParseURI ()

    xmlURIPtr	xmlParseURI		(const char * str)

Parse an URI based on RFC 3986 URI-reference = [ absoluteURI | relativeURI ] [ "#" fragment ]

`str`: | the URI string to analyze
`Returns`: | a newly built xmlURIPtr or NULL in case of error

### xmlParseURIRaw ()

    xmlURIPtr	xmlParseURIRaw		(const char * str,
    					 int raw)

Parse an URI but allows to keep intact the original fragments. URI-reference = URI / relative-ref

`str`: | the URI string to analyze
`raw`: | if 1 unescaping of URI pieces are disabled
`Returns`: | a newly built xmlURIPtr or NULL in case of error

### xmlParseURIReference ()

    int	xmlParseURIReference		(xmlURIPtr uri,
    					 const char * str)

Parse an URI reference string based on RFC 3986 and fills in the appropriate fields of the @uri structure URI-reference = URI / relative-ref

`uri`: | pointer to an URI structure
`str`: | the string to analyze
`Returns`: | 0 or the error code

### xmlPathToURI ()

    xmlChar *	xmlPathToURI		(const xmlChar * path)

Constructs an URI expressing the existing path

`path`: | the resource locator in a filesystem notation
`Returns`: | a new URI, or a duplicate of the path parameter if the construction fails. The caller is responsible for freeing the memory occupied by the returned string. If there is insufficient memory available, or the argument is NULL, the function returns NULL.

### xmlPrintURI ()

    void	xmlPrintURI			(FILE * stream,
    					 xmlURIPtr uri)

Prints the URI in the stream @stream.

`stream`: | a FILE* for the output
`uri`: | pointer to an xmlURI

### xmlSaveUri ()

    xmlChar *	xmlSaveUri		(xmlURIPtr uri)

Save the URI as an escaped string

`uri`: | pointer to an xmlURI
`Returns`: | a new string (to be deallocated by caller)

### xmlURIEscape ()

    xmlChar *	xmlURIEscape		(const xmlChar * str)

Escaping routine, does not do validity checks ! It will try to escape the chars needing this, but this is heuristic based it's impossible to be sure.

`str`: | the string of the URI to escape
`Returns`: | an copy of the string, but escaped 25 May 2001 Uses xmlParseURI and xmlURIEscapeStr to try to escape correctly according to RFC2396. - Carl Douglas

### xmlURIEscapeStr ()

    xmlChar *	xmlURIEscapeStr		(const xmlChar * str,
    					 const xmlChar * list)

This routine escapes a string to hex, ignoring reserved characters (a-z) and the characters in the exception list.

`str`: | string to escape
`list`: | exception list string of chars not to escape
`Returns`: | a new escaped string or NULL in case of error.

### xmlURIUnescapeString ()

    char *	xmlURIUnescapeString		(const char * str,
    					 int len,
    					 char * target)

Unescaping routine, but does not check that the string is an URI. The output is a direct unsigned char translation of %XX values (no encoding) Note that the length of the result can only be smaller or same size as the input string.

`str`: | the string to unescape
`len`: | the length in bytes to unescape (or <= 0 to indicate full string)
`target`: | optional destination buffer
`Returns`: | a copy of the string, but unescaped, will return NULL only in case of error