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<span id="WWW-Access"></span><div class="header">
<p>
Next: <a href="Base64-and-Binary-Data-Transmission.html" accesskey="n" rel="next">Base64 and Binary Data Transmission</a>, Previous: <a href="FTP-Objects.html" accesskey="p" rel="prev">FTP Objects</a>, Up: <a href="Networking-Utilities.html" accesskey="u" rel="up">Networking Utilities</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html" title="Index" rel="index">Index</a>]</p>
</div>
<hr>
<span id="WWW-Access-1"></span><h4 class="subsection">36.4.2 WWW Access</h4>
<p>Octave can communicate with websites across the Internet. The <code>web</code>
function will launch an external web browser to interactively view a site. The
remaining functions—<code>urlread</code>, <code>urlwrite</code>, <code>webread</code>,
<code>webwrite</code>—are internal Octave functions which can import or export
data to/from Octave and a website identified by a URL (Uniform Resource
Locator).
</p>
<span id="XREFweb"></span><dl>
<dt id="index-web">: <em><var>status</var> =</em> <strong>web</strong> <em>()</em></dt>
<dt id="index-web-1">: <em><var>status</var> =</em> <strong>web</strong> <em>(<var>url</var>)</em></dt>
<dt id="index-web-2">: <em><var>status</var> =</em> <strong>web</strong> <em>(<var>url</var>, <var>option</var>)</em></dt>
<dt id="index-web-3">: <em><var>status</var> =</em> <strong>web</strong> <em>(<var>url</var>, <var>option_1</var>, …, <var>option_N</var>)</em></dt>
<dt id="index-web-4">: <em>[<var>status</var>, <var>h</var>, <var>url</var>] =</em> <strong>web</strong> <em>(…)</em></dt>
<dd>
<p>Open <var>url</var> in the default system web browser.
</p>
<p>With no arguments given, the address <a href="https://www.octave.org">https://www.octave.org</a> is
opened.
</p>
<p>Additional options can be passed for <small>MATLAB</small> compatibility, but are
ignored.
</p>
<ul>
<li> ‘<samp>-browser</samp>’ Open <var>url</var> in the default system browser.
</li><li> ‘<samp>-new</samp>’ No effect on the system browser.
</li><li> ‘<samp>-noaddressbox</samp>’ No effect on the system browser.
</li><li> ‘<samp>-notoolbar</samp>’ No effect on the system browser.
</li></ul>
<p>The return value <var>status</var> has one of the values:
</p>
<ul>
<li> ‘<samp>0</samp>’ Found and opened system browser successfully.
</li><li> ‘<samp>1</samp>’ Cannot find the system browser.
</li><li> ‘<samp>2</samp>’ System browser found, but an error occurred.
</li></ul>
<p>The return values <var>handle</var> and <var>url</var> are currently unimplemented
but given for compatibility.
</p>
<p><strong>See also:</strong> <a href="#XREFweboptions">weboptions</a>, <a href="#XREFwebread">webread</a>, <a href="#XREFwebwrite">webwrite</a>, <a href="#XREFurlread">urlread</a>, <a href="#XREFurlwrite">urlwrite</a>.
</p></dd></dl>
<span id="XREFurlread"></span><dl>
<dt id="index-urlread">: <em><var>s</var> =</em> <strong>urlread</strong> <em>(<var>url</var>)</em></dt>
<dt id="index-urlread-1">: <em>[<var>s</var>, <var>success</var>] =</em> <strong>urlread</strong> <em>(<var>url</var>)</em></dt>
<dt id="index-urlread-2">: <em>[<var>s</var>, <var>success</var>, <var>message</var>] =</em> <strong>urlread</strong> <em>(<var>url</var>)</em></dt>
<dt id="index-urlread-3">: <em>[…] =</em> <strong>urlread</strong> <em>(<var>url</var>, <var>method</var>, <var>param</var>)</em></dt>
<dd><p>Download a remote file specified by its <var>url</var> and return its content
in string <var>s</var>.
</p>
<p>For example:
</p>
<div class="example">
<pre class="example">s = urlread ("ftp://ftp.octave.org/pub/README");
</pre></div>
<p>The variable <var>success</var> is 1 if the download was successful,
otherwise it is 0 in which case <var>message</var> contains an error
message.
</p>
<p>If no output argument is specified and an error occurs, then the error is
signaled through Octave’s error handling mechanism.
</p>
<p>This function uses libcurl. Curl supports, among others, the HTTP, FTP, and
FILE protocols. Username and password may be specified in the URL. For
example:
</p>
<div class="example">
<pre class="example">s = urlread ("http://user:password@example.com/file.txt");
</pre></div>
<p>GET and POST requests can be specified by <var>method</var> and <var>param</var>.
The parameter <var>method</var> is either ‘<samp>get</samp>’ or ‘<samp>post</samp>’ and
<var>param</var> is a cell array of parameter and value pairs.
For example:
</p>
<div class="example">
<pre class="example">s = urlread ("http://www.google.com/search", "get",
{"query", "octave"});
</pre></div>
<p><strong>See also:</strong> <a href="#XREFurlwrite">urlwrite</a>.
</p></dd></dl>
<span id="XREFurlwrite"></span><dl>
<dt id="index-urlwrite">: <em></em> <strong>urlwrite</strong> <em>(<var>url</var>, <var>localfile</var>)</em></dt>
<dt id="index-urlwrite-1">: <em><var>f</var> =</em> <strong>urlwrite</strong> <em>(<var>url</var>, <var>localfile</var>)</em></dt>
<dt id="index-urlwrite-2">: <em>[<var>f</var>, <var>success</var>] =</em> <strong>urlwrite</strong> <em>(<var>url</var>, <var>localfile</var>)</em></dt>
<dt id="index-urlwrite-3">: <em>[<var>f</var>, <var>success</var>, <var>message</var>] =</em> <strong>urlwrite</strong> <em>(<var>url</var>, <var>localfile</var>)</em></dt>
<dd><p>Download a remote file specified by its <var>url</var> and save it as
<var>localfile</var>.
</p>
<p>For example:
</p>
<div class="example">
<pre class="example">urlwrite ("ftp://ftp.octave.org/pub/README",
"README.txt");
</pre></div>
<p>The full path of the downloaded file is returned in <var>f</var>.
</p>
<p>The variable <var>success</var> is 1 if the download was successful,
otherwise it is 0 in which case <var>message</var> contains an error message.
</p>
<p>If no output argument is specified and an error occurs, then the error is
signaled through Octave’s error handling mechanism.
</p>
<p>This function uses libcurl. Curl supports, among others, the HTTP, FTP, and
FILE protocols. Username and password may be specified in the URL, for
example:
</p>
<div class="example">
<pre class="example">urlwrite ("http://username:password@example.com/file.txt",
"file.txt");
</pre></div>
<p>GET and POST requests can be specified by <var>method</var> and <var>param</var>.
The parameter <var>method</var> is either ‘<samp>get</samp>’ or ‘<samp>post</samp>’ and
<var>param</var> is a cell array of parameter and value pairs.
For example:
</p>
<div class="example">
<pre class="example">urlwrite ("http://www.google.com/search", "search.html",
"get", {"query", "octave"});
</pre></div>
<p><strong>See also:</strong> <a href="#XREFurlread">urlread</a>.
</p></dd></dl>
<span id="XREFwebread"></span><dl>
<dt id="index-webread">: <em><var>response</var> =</em> <strong>webread</strong> <em>(<var>url</var>)</em></dt>
<dt id="index-webread-1">: <em><var>response</var> =</em> <strong>webread</strong> <em>(<var>url</var>, <var>name1</var>, <var>value1</var>, …)</em></dt>
<dt id="index-webread-2">: <em><var>response</var> =</em> <strong>webread</strong> <em>(…, <var>options</var>)</em></dt>
<dd>
<p>Read content from RESTful web service.
</p>
<p>Read content from the web service specified by <var>url</var> and return the
content in <var>response</var>.
</p>
<p>All key-value pairs given (<var>name1</var>, <var>value1</var>, …) are appended
as query parameters to <var>url</var>. To place a query in the body of the
message, use <code>webwrite</code>. The web service defines the acceptable query
parameters.
</p>
<p><var>options</var> is a <code>weboptions</code> object that may be used to add other
HTTP request options. This argument can be used with either calling form.
See <code>help weboptions</code> for a complete list of supported HTTP options.
</p>
<p><strong>See also:</strong> <a href="#XREFweboptions">weboptions</a>, <a href="#XREFwebwrite">webwrite</a>.
</p></dd></dl>
<span id="XREFwebwrite"></span><dl>
<dt id="index-webwrite">: <em><var>response</var> =</em> <strong>webwrite</strong> <em>(<var>url</var>, <var>name1</var>, <var>value1</var>, …)</em></dt>
<dt id="index-webwrite-1">: <em><var>response</var> =</em> <strong>webwrite</strong> <em>(<var>url</var>, <var>data</var>)</em></dt>
<dt id="index-webwrite-2">: <em><var>response</var> =</em> <strong>webwrite</strong> <em>(…, <var>options</var>)</em></dt>
<dd>
<p>Write data to RESTful web services.
</p>
<p>Write content to the web service specified by <var>url</var> and return the
response in <var>response</var>.
</p>
<p>All key-value pairs given (<var>name1</var>, <var>value1</var>, …) are added
as pairs of query parameters to the body of request method (<code>get</code>,
<code>post</code>, <code>put</code>, etc.).
</p>
<p><var>options</var> is a <code>weboptions</code> object that may be used to add other
HTTP request options. This argument can be used with either calling form.
See <code>help weboptions</code> for a complete list of supported HTTP options.
</p>
<p><strong>See also:</strong> <a href="#XREFweboptions">weboptions</a>, <a href="#XREFwebread">webread</a>.
</p></dd></dl>
<span id="XREFweboptions"></span><dl>
<dt id="index-weboptions">: <em><var>output</var> =</em> <strong>weboptions</strong> <em>()</em></dt>
<dt id="index-weboptions-1">: <em><var>output</var> =</em> <strong>weboptions</strong> <em>(<var>name1</var>, <var>value1</var>, …)</em></dt>
<dd>
<p>Specify parameters for RESTful web services.
</p>
<p><code>weboptions</code> with no inputs returns a default <code>weboptions</code> object
to specify parameters for a request to a web service. A <code>weboptions</code>
object can be an optional input argument to the <code>webread</code> and
<code>webwrite</code> functions.
</p>
<p>Multiple name and value pair arguments may be specified in any order as
<var>name1</var>, <var>value1</var>, <var>name2</var>, <var>value2</var>, etc.
</p>
<p>The option names must match <strong>exactly</strong> one of those specified in the
table below.
</p>
<p>The following options are available:
</p>
<ul>
<li> ‘<samp>CharacterEncoding</samp>’ — Specify the character encoding of the data:
<p>‘<samp>auto</samp>’ (default), ‘<samp>UTF-8</samp>’, ‘<samp>US-ASCII</samp>’
‘<samp>auto</samp>’ chooses an encoding based on the content-type of the data.
</p>
</li><li> ‘<samp>UserAgent</samp>’ — Specify the User Agent for the connection.
<p>Default value is ‘<samp>GNU Octave/version</samp>’, where ‘<samp>version</samp>’ is the
current version of Octave as returned by <code>version</code>.
</p>
</li><li> ‘<samp>Timeout</samp>’ — Specify the timeout value for the connection in seconds.
<p>Default is 10 seconds. ‘<samp>Inf</samp>’ is not currently supported.
</p>
</li><li> ‘<samp>Username</samp>’ — User identifier for a basic HTTP connection.
<p>Default is NULL. It must be a string.
</p>
</li><li> ‘<samp>Password</samp>’ — User authentication password for HTTP connection.
<p>Default is NULL. It must be a string or character vector.
Programming Note: If you display a <code>weboption</code> object with the Password
property set, the value is displayed as a string containing
<code>'*'</code>. However, the object stores the value of the Password
property as plain text.
</p>
</li><li> ‘<samp>KeyName</samp>’ — Specify the name of an additional key to be added to
the HTTP request header. It should be coupled with ‘<samp>KeyValue</samp>’. It
must be a string or character vector.
</li><li> ‘<samp>KeyValue</samp>’ — Specify the value of the key ‘<samp>KeyName</samp>’.
<p>‘<samp>KeyName</samp>’ must be present in order to assign to this field.
</p>
</li><li> ‘<samp>HeaderFields</samp>’ — Specify the header fields for the
connection.
<p>Names and values of header fields, specified as an m-by-2 array of strings
or cell array of character vectors to add to the HTTP request header.
HeaderFields{i,1} is the name of a field and
HeaderFields{i,2} is its value.
</p>
<div class="example">
<pre class="example">weboptions ("HeaderFields", {"Content-Length" "78";"Content-Type" "application/json"})
Creates a weboptions object that contains two header fields: Content-Length
with value 78 and Content-Type with value application/json.
</pre></div>
</li><li> ‘<samp>ContentType</samp>’ — Specify the content type of the data.
<p>The following values are available:
‘<samp>auto</samp>’, ‘<samp>text</samp>’, ‘<samp>json</samp>’
</p>
<p>Default is ‘<samp>auto</samp>’. It automatically determines the content type.
All other formats like ‘<samp>audio</samp>’, ‘<samp>binary</samp>’, etc. available in
<small>MATLAB</small> are not currently supported.
</p>
</li><li> ‘<samp>ContentReader</samp>’ — Not yet implemented. Only for <small>MATLAB</small>
compatibility.
</li><li> ‘<samp>MediaType</samp>’ — Not yet implemented. Only for <small>MATLAB</small>
compatibility.
</li><li> ‘<samp>RequestMethod</samp>’ — Specifies the type of request to be made.
<p>The following methods are available:
‘<samp>get</samp>’, ‘<samp>put</samp>’, ‘<samp>post</samp>’, ‘<samp>delete</samp>’, ‘<samp>patch</samp>’
</p>
<p><code>webread</code> uses the HTTP GET method. <code>webwrite</code> uses the HTTP POST
method as default.
</p>
</li><li> ‘<samp>ArrayFormat</samp>’ – Not yet implemented. Only for <small>MATLAB</small>
compatibility.
</li><li> ‘<samp>CertificateFilename</samp>’ — Not yet implemented. Only for <small>MATLAB</small>
compatibility.
</li></ul>
<p><strong>See also:</strong> <a href="#XREFwebread">webread</a>, <a href="#XREFwebwrite">webwrite</a>.
</p></dd></dl>
<hr>
<div class="header">
<p>
Next: <a href="Base64-and-Binary-Data-Transmission.html" accesskey="n" rel="next">Base64 and Binary Data Transmission</a>, Previous: <a href="FTP-Objects.html" accesskey="p" rel="prev">FTP Objects</a>, Up: <a href="Networking-Utilities.html" accesskey="u" rel="up">Networking Utilities</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html" title="Index" rel="index">Index</a>]</p>
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