API:Options

This page is part of the MediaWiki Action API documentation.

MediaWiki version:

≥ 1.20

POST request to change preferences of the current user.

API documentation

The following documentation is the output of Special:ApiHelp/options, automatically generated by the pre-release version of MediaWiki that is running on this site (MediaWiki.org).

action=options

(main | options)

This module requires read rights.
This module requires write rights.
This module only accepts POST requests.
Source: MediaWiki
License: GPL-2.0-or-later

Change preferences of the current user.

Only options which are registered in core or in one of installed extensions, or options with keys prefixed with userjs- (intended to be used by user scripts), can be set.

https://www.mediawiki.org/wiki/Special:MyLanguage/API:Options

Specific parameters:

Other general parameters are available.

reset

Resets preferences to the site defaults.

Type: boolean (details)

resetkinds

List of types of options to reset when the reset option is set.

Values (separate with | or alternative): all, registered, registered-checkmatrix, registered-multiselect, special, unused, userjs

Default: all

change

List of changes, formatted name=value (e.g. skin=vector). If no value is given (not even an equals sign), e.g., optionname|otheroption|..., the option will be reset to its default value. If any value passed contains the pipe character (|), use the alternative multiple-value separator for correct operation.

Separate values with | or alternative.

Maximum number of values is 50 (500 for clients that are allowed higher limits).

optionname

The name of the option that should be set to the value given by optionvalue.

optionvalue

The value for the option specified by optionname. When optionname is set but optionvalue is omitted, the option will be reset to its default value.

global

What to do if the option was set globally using the GlobalPreferences extension.

ignore: Do nothing. The option remains with its previous value.
override: Add a local override.
update: Update the option globally.

One of the following values: ignore, override, update

Default: ignore

token

A "csrf" token retrieved from action=query&meta=tokens

This parameter is required.

Examples:

Reset all preferences.: api.php?action=options&reset=&token=123ABC [open in sandbox]
Change skin and hideminor preferences.: api.php?action=options&change=skin=vector|hideminor=1&token=123ABC [open in sandbox]
Reset all preferences, then set skin and nickname.: api.php?action=options&reset=&change=skin=monobook&optionname=nickname&optionvalue=[[User:Beau|Beau]]%20([[User_talk:Beau|talk]])&token=123ABC [open in sandbox]

Example

Making any POST request is a multi-step process:

Log in, via one of the methods described on API:Login .
Get an Edit token .
api.php?action=query&format=json&meta=tokens [try in ApiSandbox]
Send a POST request, with the CSRF token, to take action on a page.

The sample code below covers the final step in detail.

POST request

In this example, all parameters are passed in a GET request for the sake of simplicity. However, action=options requires POST requests; GET requests will cause an error.

Changing three options

api.php?action=options&token=58b54e0bab4a1d3fd3f7653af38e75cb%2B\&change=hideminor=1|skin=vector&optionname=nickname&optionvalue=custom-signa|ture [try in ApiSandbox]

Result
<?xml version="1.0" encoding="utf-8"?> <api options="success" />

Response

{
    "options": "success"
}

Sample code

Python

#!/usr/bin/python3

"""
    change_user_options.py

    MediaWiki API Demos
    Demo of `Options` module: POST request to change three options
    for current user

    MIT license
"""

import requests

S = requests.Session()

URL = "https://test.wikipedia.org/w/api.php"

# Step 1: GET request to fetch login token
PARAMS_0 = {
    "action": "query",
    "meta": "tokens",
    "type": "login",
    "format": "json"
}

R = S.get(url=URL, params=PARAMS_0)
DATA = R.json()

LOGIN_TOKEN = DATA['query']['tokens']['logintoken']

# Step 2: POST request to log in. Use of main account for login is not
# supported. Obtain credentials via Special:BotPasswords
# (https://www.mediawiki.org/wiki/Special:BotPasswords) for lgname & lgpassword
PARAMS_1 = {
    "action": "login",
    "lgname": "bot_user_name",
    "lgpassword": "bot_password",
    "lgtoken": LOGIN_TOKEN,
    "format": "json"
}

R = S.post(URL, data=PARAMS_1)

# Step 3: GET request to fetch CSRF token
PARAMS_2 = {
    "action": "query",
    "meta": "tokens",
    "format": "json"
}

R = S.get(url=URL, params=PARAMS_2)
DATA = R.json()

CSRF_TOKEN = DATA['query']['tokens']['csrftoken']

# Step 4: POST request to change user options
# You can check out the large list of options you can change
# at https://www.mediawiki.org/wiki/API:Options
PARAMS_3 = {
    "action": "options",
    "format": "json",
    "token": CSRF_TOKEN,
    "change": "language=en|skin=vector",
    "optionname": "nickname",
    "optionvalue": "custom-signa|ture"
}

R = S.post(URL, data=PARAMS_3)
DATA = R.json()

print(DATA)

PHP

<?php

/*
    change_user_options.php

    MediaWiki API Demos
    Demo of `Options` module: POST request to change three options
    for current user
    MIT license
*/

$endPoint = "https://test.wikipedia.org/w/api.php";

$login_Token = getLoginToken(); // Step 1
loginRequest( $login_Token ); // Step 2
$csrf_Token = getCSRFToken(); // Step 3
change_options( $csrf_Token ); // Step 4

// Step 1: GET request to fetch login token
function getLoginToken() {
	global $endPoint;

	$params1 = [
		"action" => "query",
		"meta" => "tokens",
		"type" => "login",
		"format" => "json"
	];

	$url = $endPoint . "?" . http_build_query( $params1 );

	$ch = curl_init( $url );
	curl_setopt( $ch, CURLOPT_RETURNTRANSFER, true );
	curl_setopt( $ch, CURLOPT_COOKIEJAR, "cookie.txt" );
	curl_setopt( $ch, CURLOPT_COOKIEFILE, "cookie.txt" );

	$output = curl_exec( $ch );
	curl_close( $ch );

	$result = json_decode( $output, true );
	return $result["query"]["tokens"]["logintoken"];
}

// Step 2: POST request to log in. Use of main account for login is not
// supported. Obtain credentials via Special:BotPasswords
// (https://www.mediawiki.org/wiki/Special:BotPasswords) for lgname & lgpassword
function loginRequest( $logintoken ) {
	global $endPoint;

	$params2 = [
		"action" => "login",
		"lgname" => "bot_user_name",
		"lgpassword" => "bot_password",
		"lgtoken" => $logintoken,
		"format" => "json"
	];

	$ch = curl_init();

	curl_setopt( $ch, CURLOPT_URL, $endPoint );
	curl_setopt( $ch, CURLOPT_POST, true );
	curl_setopt( $ch, CURLOPT_POSTFIELDS, http_build_query( $params2 ) );
	curl_setopt( $ch, CURLOPT_RETURNTRANSFER, true );
	curl_setopt( $ch, CURLOPT_COOKIEJAR, "cookie.txt" );
	curl_setopt( $ch, CURLOPT_COOKIEFILE, "cookie.txt" );

	$output = curl_exec( $ch );
	curl_close( $ch );

}

// Step 3: GET request to fetch CSRF token
function getCSRFToken() {
	global $endPoint;

	$params3 = [
		"action" => "query",
		"meta" => "tokens",
		"format" => "json"
	];

	$url = $endPoint . "?" . http_build_query( $params3 );

	$ch = curl_init( $url );

	curl_setopt( $ch, CURLOPT_RETURNTRANSFER, true );
	curl_setopt( $ch, CURLOPT_COOKIEJAR, "cookie.txt" );
	curl_setopt( $ch, CURLOPT_COOKIEFILE, "cookie.txt" );

	$output = curl_exec( $ch );
	curl_close( $ch );

	$result = json_decode( $output, true );
	return $result["query"]["tokens"]["csrftoken"];
}

// Step 4: POST request to edit a page
function change_options( $csrftoken ) {
	global $endPoint;

	$params4 = [
		"action" => "options",
		"change" => "language=en|skin=timeless",
		"optionname" => "nickname",
		"optionvalue" => "custom-signa|ture",
		"token" => $csrftoken,
		"format" => "json"
	];

	$ch = curl_init();

	curl_setopt( $ch, CURLOPT_URL, $endPoint );
	curl_setopt( $ch, CURLOPT_POST, true );
	curl_setopt( $ch, CURLOPT_POSTFIELDS, http_build_query( $params4 ) );
	curl_setopt( $ch, CURLOPT_RETURNTRANSFER, true );
	curl_setopt( $ch, CURLOPT_COOKIEJAR, "cookie.txt" );
	curl_setopt( $ch, CURLOPT_COOKIEFILE, "cookie.txt" );

	$output = curl_exec( $ch );
	curl_close( $ch );

	echo ( $output );
}

JavaScript

/*  
    change_user_options.js
 
    MediaWiki API Demos
    Demo of `Options` module: POST request to change two options
    for current user

    MIT license
*/

var request = require('request').defaults({jar: true}),
    url = "https://test.wikipedia.org/w/api.php";

// Step 1: GET request to fetch login token
function getLoginToken() {
    var params_0 = {
        action: "query",
        meta: "tokens",
        type: "login",
        format: "json"
    };

    request.get({ url: url, qs: params_0 }, function (error, res, body) {
        if (error) {
            return;
        }
        var data = JSON.parse(body);
        loginRequest(data.query.tokens.logintoken);
    });
}

// Step 2: POST request to log in. 
// Use of main account for login is not
// supported. Obtain credentials via Special:BotPasswords
// (https://www.mediawiki.org/wiki/Special:BotPasswords) for lgname & lgpassword
function loginRequest(login_token) {
    var params_1 = {
        action: "login",
        lgname: "bot_username",
        lgpassword: "bot_password",
        lgtoken: login_token,
        format: "json"
    };

    request.post({ url: url, form: params_1 }, function (error, res, body) {
        if (error) {
            return;
        }
        getCsrfToken();
    });
}

// Step 3: GET request to fetch CSRF token
function getCsrfToken() {
    var params_2 = {
        action: "query",
        meta: "tokens",
        format: "json"
    };

    request.get({ url: url, qs: params_2 }, function(error, res, body) {
        if (error) {
            return;
        }
        var data = JSON.parse(body);
        change_options(data.query.tokens.csrftoken);
    });
}

// Step 4: POST request to change the user options
function change_options(csrf_token) {
    var params_3 = {
        action: "options",
        change: "language=en|skin=timeless",
        token: csrf_token,
        format: "json"
    };

    request.post({ url: url, form: params_3 }, function (error, res, body) {
        if (error) {
            return;
        }
        console.log(body);
    });
}

// Start From Step 1
getLoginToken();

MediaWiki JS

/*
	change_user_options.js

	MediaWiki API Demos
	Demo of `Options` module: POST request to change three options
    for current user

	MIT License
*/

var params = {
		action: 'options',
		change: 'language=en|skin=monobook',
		optionname: 'nickname',
		optionvalue: 'custom-signa|ture',
		format: 'json'
	},
	api = new mw.Api();

api.postWithToken( 'csrf', params ).done( function ( data ) {
	console.log( data );
} );

Available options

The following is an example list obtained with /w/api.php?action=query&format=json&meta=userinfo&uiprop=options for a English Wikipedia, MediaWiki 1.40.0-wmf.14 (c526317) (December 2022) account. Most of the options listed here are defined by various MediaWiki extensions, like Echo, VisualEditor, WikiLove, or Gadgets or GrowthExperiments, among others.

* enotifusertalkpages: 0

vector-limited-width: 1
vector-page-tools-pinned: 1
flaggedrevssimpleui: 1
flaggedrevsstable: 0
flaggedrevseditdiffs: True
flaggedrevsviewdiffs: False
flaggedrevswatch: False
globaluserpage: True
rcenhancedfilters-seen-highlight-button-counter: 0
advancedsearch-disable: False
usebetatoolbar: 1
wikieditor-realtimepreview: 0
usecodemirror: 0
betafeatures-auto-enroll: False
popupsreferencepreviews: 0
popups-reference-previews: 0
visualeditor-autodisable: 0
visualeditor-betatempdisable: 0
visualeditor-editor: wikitext
visualeditor-enable: 1
visualeditor-enable-experimental: 0
visualeditor-enable-language: 0
visualeditor-hidebetawelcome: 0
visualeditor-hidetabdialog: 0
visualeditor-newwikitext: 0
visualeditor-tabs: remember-last
visualeditor-visualdiffpage: 0
mobile-editor:
math: mathml
echo-subscriptions-web-page-review: True
echo-subscriptions-email-page-review: False
echo-subscriptions-web-login-fail: True
echo-subscriptions-email-login-fail: True
echo-subscriptions-web-login-success: False
echo-subscriptions-email-login-success: True
echo-email-frequency: 0
echo-dont-email-read-notifications: False
echo-subscriptions-web-edit-thank: True
echo-subscriptions-email-edit-thank: False
discussiontools-betaenable: 0
discussiontools-editmode:
discussiontools-newtopictool: 1
discussiontools-newtopictool-createpage: 1
discussiontools-replytool: 1
discussiontools-sourcemodetoolbar: 1
discussiontools-topicsubscription: 1
discussiontools-autotopicsub: 0
discussiontools-visualenhancements: 1
usecodeeditor: 1
revisionslider-disable: False
twocolconflict-enabled: 1
eventlogging-display-web: 0
eventlogging-display-console: 0
uls-preferences:
compact-language-links: 1
echo-subscriptions-web-cx: True
cx: False
cx-enable-entrypoints: True
cx-entrypoint-fd-status: notshown
cx_campaign_newarticle_shown: False
rcshowwikidata: 0
wlshowwikibase: 0
echo-subscriptions-web-oauth-owner: True
echo-subscriptions-email-oauth-owner: True
echo-subscriptions-web-oauth-admin: True
echo-subscriptions-email-oauth-admin: True
ores-damaging-flag-rc: False
oresDamagingPref: soft
rcOresDamagingPref: soft
oresHighlight: False
oresRCHideNonDamaging: False
oresWatchlistHideNonDamaging: False
ipinfo-use-agreement: 0
twl-notified: None
ccmeonemails: 0
date: default
diffonly: 0
disablemail: 0
editfont: monospace
editondblclick: 0
editsectiononrightclick: 0
email-allow-new-users: 1
enotifminoredits: False
enotifrevealaddr: 0
enotifwatchlistpages: 0
extendwatchlist: 0
fancysig: 0
forceeditsummary: 0
gender: unknown
hideminor: 0
hidepatrolled: 0
hidecategorization: 1
imagesize: 2
minordefault: 0
newpageshidepatrolled: 0
nickname:
pst-cssjs: 1
norollbackdiff: 0
previewonfirst: 0
previewontop: 1
rcdays: 7
rcenhancedfilters-disable: 0
rclimit: 50
search-match-redirect: True
search-special-page: Search
searchlimit: 20
search-thumbnail-extra-namespaces: True
showhiddencats: False
shownumberswatching: 1
showrollbackconfirmation: 0
skin: vector
thumbsize: 4
underline: 2
uselivepreview: 0
usenewrc: 0
watchcreations: True
watchdefault: 0
watchdeletion: 0
watchuploads: 1
watchlistdays: 3
watchlisthideanons: 0
watchlisthidebots: 0
watchlisthideliu: 0
watchlisthideminor: 0
watchlisthideown: 0
watchlisthidepatrolled: 0
watchlisthidecategorization: 1
watchlistreloadautomatically: 0
watchlistunwatchlinks: 0
watchmoves: 0
watchrollback: 0
wlenhancedfilters-disable: 0
wllimit: 250
useeditwarning: 1
prefershttps: 1
requireemail: 0
skin-responsive: 1
wikilove-enabled: 1
echo-cross-wiki-notifications: 1
growthexperiments-addimage-desktop: 1
timecorrection: System|0
centralnotice-display-campaign-type-advocacy: 1
centralnotice-display-campaign-type-article-writing: 1
centralnotice-display-campaign-type-photography: 1
centralnotice-display-campaign-type-event: 1
centralnotice-display-campaign-type-fundraising: 1
centralnotice-display-campaign-type-governance: 1
centralnotice-display-campaign-type-maintenance: 1
centralnotice-display-campaign-type-special: 1
language: en
variant: en
variant-ban: ban
variant-en: en
variant-crh: crh
variant-gan: gan
variant-iu: iu
variant-kk: kk
variant-ku: ku
variant-sh: sh-latn
variant-shi: shi
variant-sr: sr
variant-tg: tg
variant-tly: tly
variant-uz: uz
variant-zh: zh
searchNs0: 1
searchNs1: 0
searchNs2: 0
searchNs3: 0
searchNs4: 0
searchNs5: 0
searchNs6: 0
searchNs7: 0
searchNs8: 0
searchNs9: 0
searchNs10: 0
searchNs11: 0
searchNs12: 0
searchNs13: 0
searchNs14: 0
searchNs15: 0
searchNs100: 0
searchNs101: 0
searchNs118: 0
searchNs119: 0
searchNs710: 0
searchNs711: 0
searchNs828: 0
searchNs829: 0
searchNs2300: 0
searchNs2301: 0
searchNs2302: 0
searchNs2303: 0
multimediaviewer-enable: 1
mf_amc_optin: 0
gadget-modrollback: 0
gadget-confirmationRollback-mobile: 1
gadget-removeAccessKeys: 0
gadget-searchFocus: 0
gadget-GoogleTrans: 0
gadget-ImageAnnotator: 0
gadget-imagelinks: 0
gadget-Navigation_popups: 0
gadget-exlinks: 0
gadget-search-new-tab: 0
gadget-PrintOptions: 0
gadget-revisionjumper: 0
gadget-Twinkle: 0
gadget-HideCentralNotice: 0
gadget-ReferenceTooltips: 1
gadget-formWizard: 1
gadget-Prosesize: 0
gadget-find-archived-section: 0
gadget-geonotice: 1
gadget-watchlist-notice: 1
gadget-WatchlistBase: 1
gadget-WatchlistGreenIndicators: 1
gadget-WatchlistGreenIndicatorsMono: 1
gadget-WatchlistChangesBold: 0
gadget-SubtleUpdatemarker: 1
gadget-defaultsummaries: 0
gadget-citations: 0
gadget-DotsSyntaxHighlighter: 0
gadget-HotCat: 0
gadget-wikEdDiff: 0
gadget-ProveIt: 0
gadget-ProveIt-classic: 0
gadget-Shortdesc-helper: 0
gadget-wikEd: 0
gadget-afchelper: 0
gadget-charinsert: 1
gadget-legacyToolbar: 0
gadget-extra-toolbar-buttons: 1
gadget-refToolbar: 1
gadget-EditNoticesOnMobile: 1
gadget-edittop: 0
gadget-UTCLiveClock: 0
gadget-purgetab: 0
gadget-ExternalSearch: 0
gadget-CollapsibleNav: 0
gadget-MenuTabsToggle: 0
gadget-dropdown-menus: 0
gadget-CategoryAboveAll: 0
gadget-addsection-plus: 0
gadget-CommentsInLocalTime: 0
gadget-OldDiff: 0
gadget-NoAnimations: 0
gadget-disablesuggestions: 0
gadget-NoSmallFonts: 0
gadget-topalert: 0
gadget-metadata: 0
gadget-JustifyParagraphs: 0
gadget-righteditlinks: 0
gadget-PrettyLog: 0
gadget-switcher: 1
gadget-SidebarTranslate: 0
gadget-Blackskin: 0
gadget-dark-mode-toggle: 0
gadget-VectorClassic: 0
gadget-widensearch: 0
gadget-DisambiguationLinks: 0
gadget-markblocked: 0
gadget-responsiveContent: 0
gadget-responsiveContentTimeless: 1
gadget-HideInterwikiSearchResults: 0
gadget-XTools-ArticleInfo: 0
gadget-ShowMessageNames: 0
gadget-DebugMode: 0
gadget-contribsrange: 0
gadget-BugStatusUpdate: 0
gadget-RTRC: 0
gadget-script-installer: 0
gadget-XFDcloser: 0
gadget-mobile-sidebar: 0
gadget-addMe: 0
gadget-NewImageThumb: 0
gadget-StickyTableHeaders: 0
gadget-MobileMaps: 0
gadget-ShowJavascriptErrors: 0
gadget-PageDescriptions: 0
gadget-autonum: 0
gadget-wide-vector-2022: 0
gadget-dark-mode: 0
cirrussearch-pref-completion-profile: fuzzy
popups: 0
echo-email-format: html
echo-subscriptions-email-system: True
echo-subscriptions-web-system: True
echo-subscriptions-push-system: True
echo-subscriptions-email-system-noemail: False
echo-subscriptions-web-system-noemail: True
echo-subscriptions-push-system-noemail: True
echo-subscriptions-email-system-emailonly: False
echo-subscriptions-web-system-emailonly: True
echo-subscriptions-push-system-emailonly: True
echo-subscriptions-email-user-rights: True
echo-subscriptions-web-user-rights: True
echo-subscriptions-push-user-rights: True
echo-subscriptions-email-other: False
echo-subscriptions-web-other: True
echo-subscriptions-push-other: True
echo-subscriptions-email-edit-user-talk: 0
echo-subscriptions-web-edit-user-talk: True
echo-subscriptions-push-edit-user-talk: True
echo-subscriptions-email-reverted: False
echo-subscriptions-web-reverted: True
echo-subscriptions-push-reverted: True
echo-subscriptions-email-article-linked: False
echo-subscriptions-web-article-linked: False
echo-subscriptions-push-article-linked: False
echo-subscriptions-email-mention: False
echo-subscriptions-web-mention: True
echo-subscriptions-push-mention: True
echo-subscriptions-email-mention-failure: False
echo-subscriptions-web-mention-failure: False
echo-subscriptions-push-mention-failure: False
echo-subscriptions-email-mention-success: False
echo-subscriptions-web-mention-success: False
echo-subscriptions-push-mention-success: False
echo-subscriptions-email-emailuser: False
echo-subscriptions-web-emailuser: True
echo-subscriptions-push-emailuser: True
echo-subscriptions-email-thank-you-edit: False
echo-subscriptions-web-thank-you-edit: True
echo-subscriptions-push-thank-you-edit: True
echo-subscriptions-push-page-review: True
echo-subscriptions-push-login-fail: True
echo-subscriptions-push-login-success: True
echo-subscriptions-push-edit-thank: True
echo-subscriptions-email-dt-subscription: False
echo-subscriptions-web-dt-subscription: True
echo-subscriptions-push-dt-subscription: True
echo-subscriptions-email-dt-subscription-archiving: False
echo-subscriptions-web-dt-subscription-archiving: True
echo-subscriptions-push-dt-subscription-archiving: True
echo-subscriptions-email-cx: False
echo-subscriptions-push-cx: True
echo-subscriptions-email-ge-mentorship: False
echo-subscriptions-web-ge-mentorship: True
echo-subscriptions-push-ge-mentorship: True
echo-subscriptions-email-wikibase-action: False
echo-subscriptions-web-wikibase-action: True
echo-subscriptions-push-wikibase-action: True
growthexperiments-help-panel-tog-help-panel: False
homepage_mobile_discovery_notice_seen: True
growthexperiments-homepage-suggestededits-guidance-blue-dot: {"vector":{"link-recommendation":true,"image-recommendation":true},"minerva":{"link-recommendation":true,"image-recommendation":true}}
growthexperiments-homepage-se-topic-filters-mode: OR
growthexperiments-homepage-enable: False
growthexperiments-homepage-pt-link: False
growthexperiments-tour-help-panel: True
growthexperiments-tour-homepage-mentorship: True
growthexperiments-tour-homepage-welcome: True
growthexperiments-tour-homepage-discovery: True
growthexperiments-tour-newimpact-discovery: False
growthexperiments-starred-mentees:
growthexperiments-mentor-dashboard-seen: 0
growthexperiments-mentor-dashboard-last-update: None
growthexperiments-mentee-overview-presets: {"usersToShow":10,"filters":{"minedits":1,"maxedits":500}}
growthexperiments-homepage-mentorship-enabled: 1
growthexperiments-mentorship-weight: 2

Possible errors

In addition to the usual stuff :

Code	Info
notloggedin	Anonymous users cannot change preferences
nochanges	No changes were requested.

Parameter history

1.21: Introduced resetkinds

Additional notes

This API is primarily intended for changing options which are registered by MediaWiki core or extensions and available on Special:Preferences.
You can also use the API to set arbitrary user options that can be used by user scripts or external editors. These options must begin with the prefix userjs-.
There is currently no limit on the number of user options you can set at once. You can store data within a user option by encoding it as a JSON string.
Providing only names of options without equal sign results in resetting them (e.g. hideminor|skin). In the case of an arbitrary userjs- key/value pair, the resetting results in its deletion.
The change parameter cannot be used to set a value which contains a pipe character |, as it is used by the API to separate options. If you need to set such a value (e.g., a user signature) use an optionname & optionvalue pair.
The following limits apply to all user options:
- The byte length of the key must be <= 255.
- The byte length of the value must be <= 65535.
- The key must consist only of ASCII letters, numbers, hyphens and underscores (a-z, A-Z, 0-9, _, -).