User-Agent policy

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As of February 15, 2010, Wikimedia sites require a HTTP User-Agent header for all requests. This was an operative decision made by the technical staff and was announced and discussed on the technical mailing list.[1][2] The rationale is, that clients that do not send a User-Agent string are mostly ill behaved scripts that cause a lot of load on the servers, without benefiting the projects. User-Agent strings that begin with non-descriptive default values, such as python-requests/x, may also be blocked from Wikimedia sites (or parts of a website, e.g. api.php).

Requests (e.g. from browsers or scripts) that do not send a descriptive User-Agent header, may encounter an error message like this:

Scripts should use an informative User-Agent string with contact information, or they may be blocked without notice.

Requests from disallowed user agents may instead encounter a less helpful error message like this:

Our servers are currently experiencing a technical problem. Please try again in a few minutes.

This change is most likely to affect scripts (bots) accessing Wikimedia websites such as Wikipedia automatically, via api.php or otherwise, and command line programs.[3] If you run a bot, please send a User-Agent header identifying the bot with an identifier that isn't going to be confused with many other bots, and supplying some way of contacting you (e.g. a userpage on the local wiki, a userpage on a related wiki using interwiki linking syntax, a URI for a relevant external website, or an email address), e.g.:

User-Agent: CoolBot/0.0 (https://example.org/coolbot/; coolbot@example.org) generic-library/0.0

The generic format is <client name>/<version> (<contact information>) <library/framework name>/<version> [<library name>/<version> ...]. Parts that are not applicable can be omitted.

If you run an automated agent, please consider following the Internet-wide convention of including the string "bot" in the User-Agent string, in any combination of lowercase or uppercase letters. This is recognized by Wikimedia's systems, and used to classify traffic and provide more accurate statistics.

Do not copy a browser's user agent for your bot, as bot-like behavior with a browser's user agent will be assumed malicious.[4] Do not use generic agents such as "curl", "lwp", "Python-urllib", and so on. For large frameworks like pywikibot, there are so many users that just "pywikibot" is likely to be somewhat vague. Including detail about the specific task/script/etc would be a good idea, even if that detail is opaque to anyone besides the operator.[5]

Web browsers generally send a User-Agent string automatically; if you encounter the above error, please refer to your browser's manual to find out how to set the User-Agent string. Note that some plugins or proxies for privacy enhancement may suppress this header. However, for anonymous surfing, it is recommended to send a generic User-Agent string, instead of suppressing it or sending an empty string. Note that other features are much more likely to identify you to a website — if you are interested in protecting your privacy, visit the Panopticlick project.

Browser-based applications written in JavaScript are typically forced to send the same User-Agent header as the browser that hosts them. This is not a violation of policy, however such applications are encouraged to include the Api-User-Agent header to supply an appropriate agent.

As of 2015, Wikimedia sites do not reject all page views and API requests from clients that do not set a User-Agent header. As such, the requirement is not automatically enforced. Rather, it may be enforced in specific cases as needed.[6]

Code examples[edit]

On Wikimedia wikis, if you don't supply a User-Agent header, or you supply an empty or generic one, your request will fail with an HTTP 403 error. Other MediaWiki installations may have similar policies.

JavaScript[edit]

If you are calling the API from browser-based JavaScript, you won't be able to influence the User-Agent header: the browser will use its own. To work around this, use the Api-User-Agent header:

// Using XMLHttpRequest
xhr.setRequestHeader( 'Api-User-Agent', 'Example/1.0' );
// Using jQuery
$.ajax( {
    url: 'https://example/...',
    data: ...,
    dataType: 'json',
    type: 'GET',
    headers: { 'Api-User-Agent': 'Example/1.0' },
} ).then( function ( data )  {
    // ..
} );
// Using mw.Api
var api = new mw.Api( {
    ajax: {
        headers: { 'Api-User-Agent': 'Example/1.0' }
    }
} );
api.get( ... ).then( function ( data ) {
    // ...
});
// Using Fetch
fetch( 'https://example/...', {
    method: 'GET',
    headers: new Headers( {
        'Api-User-Agent': 'Example/1.0'
    } )
} ).then( function ( response ) {
    return response.json();
} ).then( function ( data ) {
    // ...
});

PHP[edit]

In PHP, you can identify your user-agent with code such as this:

ini_set( 'user_agent', 'CoolBot/0.0 (https://example.org/coolbot/; coolbot@example.org)' );

cURL[edit]

Or if you use cURL:

curl_setopt( $curl, CURLOPT_USERAGENT, 'CoolBot/0.0 (https://example.org/coolbot/; coolbot@example.org)' );

Python[edit]

In Python, you can use the Requests library to set a header:

import requests

url = 'https://example/...'
headers = {'User-Agent': 'CoolBot/0.0 (https://example.org/coolbot/; coolbot@example.org)'}

response = requests.get(url, headers=headers)

Notes[edit]

See also[edit]