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diff --git a/lib/stdlib/doc/src/uri_string.xml b/lib/stdlib/doc/src/uri_string.xml new file mode 100644 index 0000000000..88d4600611 --- /dev/null +++ b/lib/stdlib/doc/src/uri_string.xml @@ -0,0 +1,359 @@ +<?xml version="1.0" encoding="utf-8" ?> +<!DOCTYPE erlref SYSTEM "erlref.dtd"> + +<erlref> + <header> + <copyright> + <year>2017</year><year>2018</year> + <holder>Ericsson AB. All Rights Reserved.</holder> + </copyright> + <legalnotice> + Licensed under the Apache License, Version 2.0 (the "License"); + you may not use this file except in compliance with the License. + You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + + Unless required by applicable law or agreed to in writing, software + distributed under the License is distributed on an "AS IS" BASIS, + WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + See the License for the specific language governing permissions and + limitations under the License. + </legalnotice> + + <title>uri_string</title> + <prepared>Péter Dimitrov</prepared> + <docno>1</docno> + <date>2018-02-07</date> + <rev>A</rev> + </header> + <module>uri_string</module> + <modulesummary>URI processing functions.</modulesummary> + <description> + <p>This module contains functions for parsing and handling URIs + (<url href="https://www.ietf.org/rfc/rfc3986.txt">RFC 3986</url>) and + form-urlencoded query strings (<url href="https://www.w3.org/TR/html52/">HTML 5.2</url>). + </p> + <p> + Parsing and serializing non-UTF-8 form-urlencoded query strings are also supported + (<url href="https://www.w3.org/TR/html50/">HTML 5.0</url>). + </p> + <p>A URI is an identifier consisting of a sequence of characters matching the syntax + rule named <em>URI</em> in <url href="https://www.ietf.org/rfc/rfc3986.txt">RFC 3986</url>. + </p> + <p> The generic URI syntax consists of a hierarchical sequence of components referred + to as the scheme, authority, path, query, and fragment:</p> + <pre> + URI = scheme ":" hier-part [ "?" query ] [ "#" fragment ] + hier-part = "//" authority path-abempty + / path-absolute + / path-rootless + / path-empty + scheme = ALPHA *( ALPHA / DIGIT / "+" / "-" / "." ) + authority = [ userinfo "@" ] host [ ":" port ] + userinfo = *( unreserved / pct-encoded / sub-delims / ":" ) + + reserved = gen-delims / sub-delims + gen-delims = ":" / "/" / "?" / "#" / "[" / "]" / "@" + sub-delims = "!" / "$" / "&" / "'" / "(" / ")" + / "*" / "+" / "," / ";" / "=" + + unreserved = ALPHA / DIGIT / "-" / "." / "_" / "~" + </pre><br></br> + <p>The interpretation of a URI depends only on the characters used and not on how those + characters are represented in a network protocol.</p> + <p>The functions implemented by this module cover the following use cases:</p> + <list type="bulleted"> + <item>Parsing URIs into its components and returing a map<br></br> + <seealso marker="#parse/1"><c>parse/1</c></seealso> + </item> + <item>Recomposing a map of URI components into a URI string<br></br> + <seealso marker="#recompose/1"><c>recompose/1</c></seealso> + </item> + <item>Changing inbound binary and percent-encoding of URIs<br></br> + <seealso marker="#transcode/2"><c>transcode/2</c></seealso> + </item> + <item>Transforming URIs into a normalized form<br></br> + <seealso marker="#normalize/1"><c>normalize/1</c></seealso><br></br> + <seealso marker="#normalize/2"><c>normalize/2</c></seealso> + </item> + <item>Composing form-urlencoded query strings from a list of key-value pairs<br></br> + <seealso marker="#compose_query/1"><c>compose_query/1</c></seealso><br></br> + <seealso marker="#compose_query/2"><c>compose_query/2</c></seealso> + </item> + <item>Dissecting form-urlencoded query strings into a list of key-value pairs<br></br> + <seealso marker="#dissect_query/1"><c>dissect_query/1</c></seealso> + </item> + </list> + <p>There are four different encodings present during the handling of URIs:</p> + <list type="bulleted"> + <item>Inbound binary encoding in binaries</item> + <item>Inbound percent-encoding in lists and binaries</item> + <item>Outbound binary encoding in binaries</item> + <item>Outbound percent-encoding in lists and binaries</item> + </list> + <p>Functions with <c>uri_string()</c> argument accept lists, binaries and + mixed lists (lists with binary elements) as input type. All of the functions but + <c>transcode/2</c> expects input as lists of unicode codepoints, UTF-8 encoded binaries + and UTF-8 percent-encoded URI parts ("%C3%B6" corresponds to the unicode character "ö").</p> + <p>Unless otherwise specified the return value type and encoding are the same as the input + type and encoding. That is, binary input returns binary output, list input returns a list + output but mixed input returns list output.</p> + <p>In case of lists there is only percent-encoding. In binaries, however, both binary encoding + and percent-encoding shall be considered. <c>transcode/2</c> provides the means to convert + between the supported encodings, it takes a <c>uri_string()</c> and a list of options + specifying inbound and outbound encodings.</p> + <p><url href="https://www.ietf.org/rfc/rfc3986.txt">RFC 3986</url> does not mandate any specific + character encoding and it is usually defined by the protocol or surrounding text. This library + takes the same assumption, binary and percent-encoding are handled as one configuration unit, + they cannot be set to different values.</p> + </description> + + <datatypes> + <datatype> + <name name="error"/> + <desc> + <p>Error tuple indicating the type of error. Possible values of the second component:</p> + <list type="bulleted"> + <item><c>invalid_character</c></item> + <item><c>invalid_encoding</c></item> + <item><c>invalid_input</c></item> + <item><c>invalid_map</c></item> + <item><c>invalid_percent_encoding</c></item> + <item><c>invalid_scheme</c></item> + <item><c>invalid_uri</c></item> + <item><c>invalid_utf8</c></item> + <item><c>missing_value</c></item> + </list> + <p>The third component is a term providing additional information about the + cause of the error.</p> + </desc> + </datatype> + <datatype> + <name name="uri_map"/> + <desc> + <p>Map holding the main components of a URI.</p> + </desc> + </datatype> + <datatype> + <name name="uri_string"/> + <desc> + <p>List of unicode codepoints, a UTF-8 encoded binary, or a mix of the two, + representing an <url href="https://www.ietf.org/rfc/rfc3986.txt">RFC 3986</url> + compliant URI (<em>percent-encoded form</em>). + A URI is a sequence of characters from a very limited set: the letters of + the basic Latin alphabet, digits, and a few special characters.</p> + </desc> + </datatype> + </datatypes> + + <funcs> + + <func> + <name name="compose_query" arity="1"/> + <fsummary>Compose urlencoded query string.</fsummary> + <desc> + <p>Composes a form-urlencoded <c><anno>QueryString</anno></c> based on a + <c><anno>QueryList</anno></c>, a list of non-percent-encoded key-value pairs. + Form-urlencoding is defined in section + 4.10.21.6 of the <url href="https://www.w3.org/TR/html52/">HTML 5.2</url> + specification and in section 4.10.22.6 of the + <url href="https://www.w3.org/TR/html50/">HTML 5.0</url> specification for + non-UTF-8 encodings. + </p> + <p>See also the opposite operation <seealso marker="#dissect_query/1"> + <c>dissect_query/1</c></seealso>. + </p> + <p><em>Example:</em></p> + <pre> +1> <input>uri_string:compose_query([{"foo bar","1"},{"city","örebro"}]).</input> +<![CDATA["foo+bar=1&city=%C3%B6rebro"]]> +2> <![CDATA[uri_string:compose_query([{<<"foo bar">>,<<"1">>}, +2> {<<"city">>,<<"örebro"/utf8>>}]).]]> +<![CDATA[<<"foo+bar=1&city=%C3%B6rebro">>]]> + </pre> + </desc> + </func> + + <func> + <name name="compose_query" arity="2"/> + <fsummary>Compose urlencoded query string.</fsummary> + <desc> + <p>Same as <c>compose_query/1</c> but with an additional + <c><anno>Options</anno></c> parameter, that controls the encoding ("charset") + used by the encoding algorithm. There are two supported encodings: <c>utf8</c> + (or <c>unicode</c>) and <c>latin1</c>. + </p> + <p>Each character in the entry's name and value that cannot be expressed using + the selected character encoding, is replaced by a string consisting of a U+0026 + AMPERSAND character (<![CDATA[&]]>), a "#" (U+0023) character, one or more ASCII + digits representing the Unicode code point of the character in base ten, and + finally a ";" (U+003B) character. + </p> + <p>Bytes that are out of the range 0x2A, 0x2D, 0x2E, 0x30 to 0x39, 0x41 to 0x5A, 0x5F, + 0x61 to 0x7A, are percent-encoded (U+0025 PERCENT SIGN character (%) followed by + uppercase ASCII hex digits representing the hexadecimal value of the byte). + </p> + <p>See also the opposite operation <seealso marker="#dissect_query/1"> + <c>dissect_query/1</c></seealso>. + </p> + <p><em>Example:</em></p> + <pre> +1> <input>uri_string:compose_query([{"foo bar","1"},{"city","örebro"}],</input> +1> [{encoding, latin1}]). +<![CDATA["foo+bar=1&city=%F6rebro" +2> uri_string:compose_query([{<<"foo bar">>,<<"1">>}, +2> {<<"city">>,<<"東京"/utf8>>}], [{encoding, latin1}]).]]> +<![CDATA[<<"foo+bar=1&city=%26%2326481%3B%26%2320140%3B">>]]> + </pre> + </desc> + </func> + + <func> + <name name="dissect_query" arity="1"/> + <fsummary>Dissect query string.</fsummary> + <desc> + <p>Dissects an urlencoded <c><anno>QueryString</anno></c> and returns a + <c><anno>QueryList</anno></c>, a list of non-percent-encoded key-value pairs. + Form-urlencoding is defined in section + 4.10.21.6 of the <url href="https://www.w3.org/TR/html52/">HTML 5.2</url> + specification and in section 4.10.22.6 of the + <url href="https://www.w3.org/TR/html50/">HTML 5.0</url> specification for + non-UTF-8 encodings. + </p> + <p>See also the opposite operation <seealso marker="#compose_query/1"> + <c>compose_query/1</c></seealso>. + </p> + <p><em>Example:</em></p> + <pre> +1> <input><![CDATA[uri_string:dissect_query("foo+bar=1&city=%C3%B6rebro").]]></input> +[{"foo bar","1"},{"city","örebro"}] +2> <![CDATA[uri_string:dissect_query(<<"foo+bar=1&city=%26%2326481%3B%26%2320140%3B">>).]]> +<![CDATA[[{<<"foo bar">>,<<"1">>}, + {<<"city">>,<<230,157,177,228,186,172>>}] ]]> + </pre> + </desc> + </func> + + <func> + <name name="normalize" arity="1"/> + <fsummary>Syntax-based normalization.</fsummary> + <desc> + <p>Transforms an <c><anno>URI</anno></c> into a normalized form + using Syntax-Based Normalization as defined by + <url href="https://www.ietf.org/rfc/rfc3986.txt">RFC 3986</url>.</p> + <p>This function implements case normalization, percent-encoding + normalization, path segment normalization and scheme based normalization + for HTTP(S) with basic support for FTP, SSH, SFTP and TFTP.</p> + <p><em>Example:</em></p> + <pre> +1> <input>uri_string:normalize("/a/b/c/./../../g").</input> +"/a/g" +2> <![CDATA[uri_string:normalize(<<"mid/content=5/../6">>).]]> +<![CDATA[<<"mid/6">>]]> +3> uri_string:normalize("http://localhost:80"). +"https://localhost/" +4> <input>uri_string:normalize(#{scheme => "http",port => 80,path => "/a/b/c/./../../g",</input> +4> host => "localhost-örebro"}). +"http://localhost-%C3%B6rebro/a/g" + </pre> + </desc> + </func> + + <func> + <name name="normalize" arity="2"/> + <fsummary>Syntax-based normalization.</fsummary> + <desc> + <p>Same as <c>normalize/1</c> but with an additional + <c><anno>Options</anno></c> parameter, that controls if the normalized URI + shall be returned as an uri_map(). + There is one supported option: <c>return_map</c>. + </p> + <p><em>Example:</em></p> + <pre> +1> <input>uri_string:normalize("/a/b/c/./../../g", [return_map]).</input> +#{path => "/a/g"} +2> <![CDATA[uri_string:normalize(<<"mid/content=5/../6">>, [return_map]).]]> +<![CDATA[#{path => <<"mid/6">>}]]> +3> uri_string:normalize("http://localhost:80", [return_map]). +#{scheme => "http",path => "/",host => "localhost"} +4> <input>uri_string:normalize(#{scheme => "http",port => 80,path => "/a/b/c/./../../g",</input> +4> host => "localhost-örebro"}, [return_map]). +#{scheme => "http",path => "/a/g",host => "localhost-örebro"} + </pre> + </desc> + </func> + + <func> + <name name="parse" arity="1"/> + <fsummary>Parse URI into a map.</fsummary> + <desc> + <p>Parses an <url href="https://www.ietf.org/rfc/rfc3986.txt">RFC 3986</url> + compliant <c>uri_string()</c> into a <c>uri_map()</c>, that holds the parsed + components of the <c>URI</c>. + If parsing fails, an error tuple is returned.</p> + <p>See also the opposite operation <seealso marker="#recompose/1"> + <c>recompose/1</c></seealso>.</p> + <p><em>Example:</em></p> + <pre> +1> <input>uri_string:parse("foo://[email protected]:8042/over/there?name=ferret#nose").</input> +#{fragment => "nose",host => "example.com", + path => "/over/there",port => 8042,query => "name=ferret", + scheme => foo,userinfo => "user"} +2> <![CDATA[uri_string:parse(<<"foo://[email protected]:8042/over/there?name=ferret">>).]]> +<![CDATA[#{host => <<"example.com">>,path => <<"/over/there">>, + port => 8042,query => <<"name=ferret">>,scheme => <<"foo">>, + userinfo => <<"user">>}]]> + </pre> + </desc> + </func> + + <func> + <name name="recompose" arity="1"/> + <fsummary>Recompose URI.</fsummary> + <desc> + <p>Creates an <url href="https://www.ietf.org/rfc/rfc3986.txt">RFC 3986</url> compliant + <c><anno>URIString</anno></c> (percent-encoded), based on the components of + <c><anno>URIMap</anno></c>. + If the <c><anno>URIMap</anno></c> is invalid, an error tuple is returned.</p> + <p>See also the opposite operation <seealso marker="#parse/1"> + <c>parse/1</c></seealso>.</p> + <p><em>Example:</em></p> + <pre> +1> <input>URIMap = #{fragment => "nose", host => "example.com", path => "/over/there",</input> +1> port => 8042, query => "name=ferret", scheme => "foo", userinfo => "user"}. +#{fragment => "top",host => "example.com", + path => "/over/there",port => 8042,query => "?name=ferret", + scheme => foo,userinfo => "user"} + +2> <input>uri_string:recompose(URIMap).</input> +"foo://example.com:8042/over/there?name=ferret#nose"</pre> + </desc> + </func> + + <func> + <name name="transcode" arity="2"/> + <fsummary>Transcode URI.</fsummary> + <desc> + <p>Transcodes an <url href="https://www.ietf.org/rfc/rfc3986.txt">RFC 3986</url> + compliant <c><anno>URIString</anno></c>, + where <c><anno>Options</anno></c> is a list of tagged tuples, specifying the inbound + (<c>in_encoding</c>) and outbound (<c>out_encoding</c>) encodings. <c>in_encoding</c> + and <c>out_encoding</c> specifies both binary encoding and percent-encoding for the + input and output data. Mixed encoding, where binary encoding is not the same as + percent-encoding, is not supported. + If an argument is invalid, an error tuple is returned.</p> + <p><em>Example:</em></p> + <pre> +1> <input><![CDATA[uri_string:transcode(<<"foo%00%00%00%F6bar"/utf32>>,]]></input> +1> [{in_encoding, utf32},{out_encoding, utf8}]). +<![CDATA[<<"foo%C3%B6bar"/utf8>>]]> +2> uri_string:transcode("foo%F6bar", [{in_encoding, latin1}, +2> {out_encoding, utf8}]). +"foo%C3%B6bar" + </pre> + </desc> + </func> + + </funcs> +</erlref> |