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libpq: URI parsing fixes

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Drop special handling of host component with slashes to mean
Unix-domain socket.  Specify it as separate parameter or using
percent-encoding now.

Allow omitting username, password, and port even if the corresponding
designators are present in URI.

Handle percent-encoding in query parameter keywords.

Alex Shulgin

some documentation improvements by myself
This commit is contained in:
Peter Eisentraut
2012-05-28 22:44:34 +03:00
parent 388d251679
commit 2d612abd4d
4 changed files with 272 additions and 259 deletions
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219
doc/src/sgml/libpq.sgml
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@ -711,6 +711,124 @@ PGPing PQping(const char *conninfo);
</variablelist>
</para>
<sect2 id="libpq-connstring">
<title>Connection Strings</title>
<indexterm zone="libpq-connstring">
<primary><literal>conninfo</literal></primary>
</indexterm>
<indexterm zone="libpq-connstring">
<primary><literal>URI</literal></primary>
</indexterm>
<para>
Several <application>libpq</> functions parse a user-specified string to obtain
connection parameters. There are two accepted formats for these strings:
plain <literal>keyword = value</literal> strings
and <ulink url="http://www.ietf.org/rfc/rfc3986.txt">RFC
3986</ulink> URIs.
</para>
<sect3>
<title>Keyword/Value Connection Strings</title>
<para>
In the first format, each parameter setting is in the form
<literal>keyword = value</literal>. Spaces around the equal sign are
optional. To write an empty value, or a value containing spaces, surround it
with single quotes, e.g., <literal>keyword = 'a value'</literal>. Single
quotes and backslashes within
the value must be escaped with a backslash, i.e., <literal>\'</literal> and
<literal>\\</literal>.
</para>
<para>
Example:
<programlisting>
host=localhost port=5432 dbname=mydb connect_timeout=10
</programlisting>
</para>
<para>
The recognized parameter key words are listed in <xref
linkend="libpq-paramkeywords">.
</para>
</sect3>
<sect3>
<title>Connection URIs</title>
<para>
The general form for a connection <acronym>URI</acronym> is:
<synopsis>
postgresql://[user[:password]@][netloc][:port][/dbname][?param1=value1&amp;...]
</synopsis>
</para>
<para>
The <acronym>URI</acronym> scheme designator can be either
<literal>postgresql://</literal> or <literal>postgres://</literal>. Each
of the <acronym>URI</acronym> parts is optional. The following examples
illustrate valid <acronym>URI</acronym> syntax uses:
<programlisting>
postgresql://
postgresql://localhost
postgresql://localhost:5433
postgresql://localhost/mydb
postgresql://user@localhost
postgresql://user:secret@localhost
postgresql://other@localhost/otherdb?connect_timeout=10&amp;application_name=myapp
</programlisting>
Components of the hierarchical part of the <acronym>URI</acronym> can also
be given as parameters. For example:
<programlisting>
postgresql:///mydb?host=localhost&amp;port=5433
</programlisting>
</para>
<para>
Percent-encoding may be used to include symbols with special meaning in any
of the <acronym>URI</acronym> parts.
</para>
<para>
Any connection parameters not corresponding to key words listed in <xref
linkend="libpq-paramkeywords"> are ignored and a warning message about them
is sent to <filename>stderr</filename>.
</para>
<para>
For improved compatibility with JDBC connection <acronym>URI</acronym>s,
instances of parameter <literal>ssl=true</literal> are translated into
<literal>sslmode=require</literal>.
</para>
<para>
The host part may be either hostname or an IP address. To specify an
IPv6 host address, enclose it in square brackets:
<synopsis>
postgresql://[2001:db8::1234]/database
</synopsis>
</para>
<para>
The host component is interpreted as described for the parameter <xref
linkend="libpq-connect-host">. In particular, a Unix-domain socket
connection is chosen if the host part is either empty or starts with a
slash, otherwise a TCP/IP connection is initiated. Note, however, that the
slash is a reserved character in the hierarchical part of the URI. So, to
specify a non-standard Unix-domain socket directory, either omit the host
specification in the URI and specify the host as a parameter, or
percent-encode the path in the host component of the URI:
<programlisting>
postgresql:///dbname?host=/var/lib/postgresql
postgresql://%2Fvar%2Flib%2Fpostgresql/dbname
</programlisting>
</para>
</sect3>
</sect2>
<sect2 id="libpq-paramkeywords">
<title>Parameter Key Words</title>
@ -1220,107 +1338,6 @@ PGPing PQping(const char *conninfo);
</variablelist>
</para>
</sect2>
<sect2 id="libpq-connstring">
<title>Connection Strings</title>
<indexterm zone="libpq-connstring">
<primary><literal>conninfo</literal></primary>
</indexterm>
<indexterm zone="libpq-connstring">
<primary><literal>URI</literal></primary>
</indexterm>
<para>
Several <application>libpq</> functions parse a user-specified string to obtain
connection parameters. There are two accepted formats for these strings:
plain <literal>keyword = value</literal> strings, and URIs.
</para>
<para>
In the first format, each parameter setting is in the form
<literal>keyword = value</literal>. Spaces around the equal sign are
optional. To write an empty value, or a value containing spaces, surround it
with single quotes, e.g., <literal>keyword = 'a value'</literal>. Single
quotes and backslashes within
the value must be escaped with a backslash, i.e., <literal>\'</literal> and
<literal>\\</literal>.
</para>
<para>
The currently recognized parameter key words are listed in
<xref linkend="libpq-paramkeywords">.
</para>
<para>
The general form for connection <acronym>URI</acronym> is the
following:
<synopsis>
postgresql://[user[:password]@][unix-socket][:port[/dbname]][?param1=value1&amp;...]
postgresql://[user[:password]@][net-location][:port][/dbname][?param1=value1&amp;...]
</synopsis>
</para>
<para>
The <acronym>URI</acronym> designator can be either
<literal>postgresql://</literal> or <literal>postgres://</literal> and
each of the <acronym>URI</acronym> parts is optional. The following
examples illustrate valid <acronym>URI</acronym> syntax uses:
<synopsis>
postgresql://
postgresql://localhost
postgresql://localhost:5433
postgresql://localhost/mydb
postgresql://user@localhost
postgresql://user:secret@localhost
postgresql://other@localhost/otherdb
</synopsis>
</para>
<para>
Percent-encoding may be used to include a symbol with special meaning in
any of the <acronym>URI</acronym> parts.
</para>
<para>
Additional connection parameters may optionally follow the base <acronym>URI</acronym>.
Any connection parameters not corresponding to key words listed
in <xref linkend="libpq-paramkeywords"> are ignored and a warning message
about them is sent to <filename>stderr</filename>.
</para>
<para>
For improved compatibility with JDBC connection <acronym>URI</acronym>
syntax, instances of parameter <literal>ssl=true</literal> are translated
into <literal>sslmode=require</literal> (see above.)
</para>
<para>
The host part may be either hostname or an IP address. To specify an
IPv6 host address, enclose it in square brackets:
<synopsis>
postgresql://[2001:db8::1234]/database
</synopsis>
As a special case, a host part which starts with <symbol>/</symbol> is
treated as a local Unix socket directory to look for the connection
socket special file:
<synopsis>
postgresql:///path/to/pgsql/socket/dir
</synopsis>
The whole connection string up to the extra parameters designator
(<symbol>?</symbol>) or the port designator (<symbol>:</symbol>) is treated
as the absolute path to the socket directory
(<literal>/path/to/pgsql/socket/dir</literal> in this example.) To specify
a non-default database name in this case you can use either of the following
syntaxes:
<synopsis>
postgresql:///path/to/pgsql/socket/dir?dbname=otherdb
postgresql:///path/to/pgsql/socket/dir:5432/otherdb
</synopsis>
</para>
</sect2>
</sect1>
<sect1 id="libpq-status">