Module Url
The Url module performs a number of useful operations on URL strings. For example, it is sometimes useful to break up a URL into its constituent parts, modify some of them, and glue the parts back together again. In the same manner, query strings (the part of a URL that follows the question mark) also need to be manipulated.
For example, given the URL (a typical AltaVista query)
http://www.altavista.digital.com/cgi-bin/query
?pg=q&kl=XX&q=%2Bjava+%2Bcoffee
the Split function will return an object as follows:
[.
query = "?pg=q&kl=XX&q=%2Bjava+%2Bcoffee",
path = "/cgi-bin/query",
host = "www.altavista.digital.com",
ref = "",
scheme = "http"
.]
Applying the
SplitQuery function to the query field of this object will return the following object:
[. kl = "XX", pg = "q", q = "+java +coffee" .]
Behind the scenes, decoding the query string involves calls to the
Decode function to remove the character encodings (eg. %@B and so on).
The Glue and
GlueQuery functions will glue those objects back together again. The field names generated by the Split function are summarized in
See URL constituents
. Note that the current implementation can process only the http, ftp, and file protocol schemes.
Module Url
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Function
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Description
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Decode(s: string): string
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Decodes a string in the MIME type encoding "x-www-form-urlencoded". The complementary function is called Encode.
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Encode(s: string): string
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Encodes a string in the MIME type encoding "x-www-form-urlencoded" (which is generally used to encode input form parameters). The complementary function is called Decode.
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Glue(obj: object): string
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Takes the constituent parts of a URL (as broken up by Split), and glues them together to form a URL again.
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GlueQuery(obj: object): string
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Given an object constructed from SplitQuery, GlueQuery returns the original query string again.
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Resolve(base: string, rel: string): string
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Given the base URL base and the relative URL rel, return the resolved URL.
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Split(url: string): object
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Splits a URL into its constituent parts (like scheme, host, path, query etc.). Each part becomes a field of the object returned.
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SplitQuery(query: string): object
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Splits a query string into its constituent parts. Each part becomes a field of the object returned. Query strings typically follow the ? in URLs.
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URL constituents
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Field name
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Used in
schemes
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Description
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scheme
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All
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http, ftp, file, etc.
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host
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http, ftp, file
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Host name.
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port
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http, ftp
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TCP/IP connection port.
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path
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http, ftp, file
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Full path name of the addressed resource.
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query
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http
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Query string (after '?' in URL)
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ref
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http, file
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Anchor reference string (after '#' in URL).
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user
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ftp
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Login user name.
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password
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ftp
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Login password.
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type
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ftp
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File transfer type 'a', 'i', 'd'.
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url
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Unknown schemes
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Contains the complete URL because no constituents could be extracted (because the scheme is unknown).
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