Utiliser JSON dans le protocole de données Google
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Avertissement: Cette page concerne les anciennes API Google, les API Google Data. Elle ne concerne que les API répertoriées dans l'annuaire des API Google Data, dont la plupart ont été remplacées par de nouvelles API. Pour en savoir plus sur une nouvelle API spécifique, consultez sa documentation. Pour en savoir plus sur l'autorisation des requêtes avec une API plus récente, consultez Authentification et autorisation des comptes Google.
Cet article concerne le format JSON, car il est utilisé dans le cadre du protocole de données Google. Pour en savoir plus sur le protocole, consultez le guide du développeur.
Vous pouvez utiliser JSON avec n'importe quel langage de programmation, mais les exemples présentés dans ce document sont en JavaScript.
À propos des flux JSON et XML
Un service de données Google crée un flux au format JSON en convertissant le flux XML à l'aide des règles suivantes:
Basic
- Le flux est représenté sous la forme d'un objet JSON. Chaque élément ou attribut imbriqué est représenté sous la forme d'une propriété de nom/valeur de l'objet.
- Les attributs sont convertis en propriétés de chaîne.
- Les éléments enfants sont convertis en propriétés d'objet.
- Les éléments qui peuvent apparaître plusieurs fois sont convertis en propriétés de tableau.
- Les valeurs textuelles des balises sont converties en propriétés
$t.
Namespace
- Si un élément possède un alias d'espace de noms, l'alias et l'élément sont concaténés à l'aide de "$". Par exemple,
ns:element devient ns$element.
XML
- Les attributs de version et d'encodage XML sont respectivement convertis en attributs de version et d'encodage de l'élément racine.
L'exemple suivant présente les versions XML et JSON du même flux. Les onglets sont présentés sous forme de onglets pour vous permettre de les comparer facilement.
XML
<?xml version="1.0" encoding="UTF-8" ?>
<feed xmlns="http://www.w3.org/2005/Atom"
xmlns:openSearch="http://a9.com/-/spec/opensearchrss/1.0/"
xmlns:gd="http://schemas.google.com/g/2005"
xmlns:gCal="http://schemas.google.com/gCal/2005">
<id>...</id>
<updated>2006-11-12T21:25:30.000Z</updated>
<title type="text">Google Developer Events</title>
<subtitle type="text">The calendar contains information about upcoming
developer conferences at which Google will be speaking, along with
other developer-related events.</subtitle>
<link rel="http://schemas.google.com/g/2005#feed"
type="application/atom+xml" href="..." />
<link rel="self" type="application/atom+xml" href="..." />
<author>
<name>Google Developer Calendar</name>
<email>developer-calendar@google.com</email>
</author>
<generator version="1.0"
uri="http://www.google.com/calendar">Google Calendar</generator>
<openSearch:startIndex>1</openSearch:startIndex>
<openSearch:itemsPerPage>25</openSearch:itemsPerPage>
<gCal:timezone value="America/Los_Angeles" />
<entry>
<id>...</id>
<published>2006-11-12T21:25:30.000Z</published>
<updated>2006-11-12T21:25:30.000Z</updated>
<category scheme="..." term="..." />
<title type="text">WebmasterWorld PubCon 2006:
Google Developer Tools in General</title>
<content type="text">Google is sponsoring at
<a href="http://www.pubcon.com/">WebmasterWorld PubCon 2006</a>. Come and
visit us at the booth or join us for an evening demo reception where we
will be talking "5 ways to enhance your website with Google Code".
After all, it is Vegas, baby! See you soon.</content>
<link rel="alternate" type="text/html" href="..." title="alternate" />
<link rel="self" type="application/atom+xml" href="..." />
<author>
<name>Google Developer Calendar</name>
<email>developer-calendar@google.com</email>
</author>
<gCal:sendEventNotifications value="true" />
<gd:comments>
<gd:feedLink href="..." />
</gd:comments>
<gd:transparency value="..." />
<gd:eventStatus value="..." />
<gd:where valueString="3150 Paradise Road, Las Vegas, NV 89109" />
<gd:when startTime="2006-11-15" endTime="2006-11-17">
<gd:reminder minutes="10" />
</gd:when>
</entry>
...
</feed>
JSON
{
"version": "1.0",
"encoding": "UTF-8",
"feed": {
"xmlns": "http://www.w3.org/2005/Atom",
"xmlns$openSearch": "http://a9.com/-/spec/opensearchrss/1.0/",
"xmlns$gd": "http://schemas.google.com/g/2005",
"xmlns$gCal": "http://schemas.google.com/gCal/2005",
"id": {"$t": "..."},
"updated": {"$t": "2006-11-12T21:25:30.000Z"},
"title": {
"type": "text",
"$t": "Google Developer Events"
},
"subtitle": {
"type": "text",
"$t": "The calendar contains information about upcoming developer
conferences at which Google will be speaking, along with other
developer-related events."
},
"link": [{
"rel": "...",
"type": "application/atom+xml",
"href": "..."
},{
"rel": "self",
"type": "application/atom+xml",
"href": "..."
}],
"author": [{
"name": {"$t": "Google Developer Calendar"},
"email": {"$t": "developer-calendar@google.com"}
}],
"generator":{
"version": "1.0",
"uri": "http://www.google.com/calendar",
"$t": "Google Calendar"
},
"openSearch$startIndex": {"$t": "1"},
"openSearch$itemsPerPage": {"$t": "25"},
"gCal$timezone": {"value": "America/Los_Angeles"},
"entry": [{
"id": {"$t": "..."},
"published": {"$t": "2006-11-12T21:25:30.000Z"},
"updated": {"$t": "2006-11-12T21:25:30.000Z"},
"category": [{
"scheme": "...",
"term": "..."
}],
"title":{
"type": "text",
"$t": "WebmasterWorld PubCon 2006: Google Developer Tools in General"
},
"content": {
"type": "text",
"$t": "Google is sponsoring at
<a href="http://www.pubcon.com/">WebmasterWorld PubCon 2006</a>.
\nCome and visit us at the booth or join us for an evening demo
reception where we will be talking "5 ways to enhance your website
with Google Code".\nAfter all,\nit is Vegas, baby! See you soon."
},
"link": [{
"rel": "alternate",
"type": "text/html",
"href": "...",
"title": "alternate"
},{
"rel": "self",
"type": "application/atom+xml",
"href": "..."
}],
"author": [{
"name": {"$t": "Google Developer Calendar"},
"email": {"$t": "developer-calendar@google.com"}
}],
"gd$transparency": {"value": "http://schemas.google.com/g/2005#event.opaque"},
"gd$eventStatus": {"value": "http://schemas.google.com/g/2005#event.confirmed"},
"gd$comments": {"gd$feedLink": {"href": "..."}},
"gCal$sendEventNotifications": {"value": "true"},
"gd$when": [{
"startTime": "2006-11-15",
"endTime": "2006-11-17",
"gd$reminder": [{"minutes": "10"}]
}],
"gd$where": [{"valueString": "3150 Paradise Road,Las Vegas,NV 89109"}]},
}]
}
}
Demander et utiliser des flux JSON
Atom est le format par défaut de Google Data. Si vous ne spécifiez pas de paramètre alt dans votre requête, vous recevez un flux Atom.
Remarque: Les bibliothèques clientes Google Data ne sont actuellement pas compatibles avec JSON.
Sortie JSON
Pour demander une réponse au format JSON, utilisez le paramètre alt=json.
Par exemple, pour demander le flux d'agenda pour les développeurs Google au format JSON, envoyez la requête suivante:
http://www.google.com/calendar/feeds/developer-calendar@google.com/public/full?alt=json
Résultat JSON-in-script
Pour demander une réponse qui encapsule le code JSON dans un tag de script, utilisez le paramètre alt=json-in-script et ajoutez une fonction de rappel en ajoutant le paramètre callback=functionName.
http://www.google.com/calendar/feeds/developer-calendar@google.com/public/full?alt=json-in-script&callback=myFunction
Les fonctions de rappel vous permettent de contourner certains des problèmes de sécurité inter-domaines que vous pouvez rencontrer dans le code JavaScript côté client. En général, les navigateurs vous empêchent de charger des fichiers sur plusieurs domaines en raison de failles de sécurité potentielles et des attaques inter-domaines qui pourraient en résulter.
Le format JSON-in-script vous permet de contourner ces restrictions en chargeant la réponse dans un tag de script sur le client. Cela signifie que vous pouvez utiliser la réponse à d'autres endroits dans votre code JavaScript sur cette page.
La sortie JSON est chargée lorsque la page est chargée. Aucun autre truc n'est nécessaire.
L'application fonctionnelle ci-dessous illustre cette technique:
<h3>Upcoming Google Developer Events</h3>
<div id="agenda"></div>
<script>
function listEvents(root) {
var feed = root.feed;
var entries = feed.entry || [];
var html = ['<ul>'];
for (var i = 0; i < entries.length; ++i) {
var entry = entries[i];
var title = (entry.title.type == 'html') ? entry.title.$t : escape(entry.title.$t);
var start = (entry['gd$when']) ? entry['gd$when'][0].startTime : "";
html.push('<li>', start, ' ', title, '</li>');
}
html.push('</ul>');
document.getElementById("agenda").innerHTML = html.join("");
}
</script>
<script src="http://www.google.com/calendar/feeds/developer-calendar@google.com/public/full?alt=json-in-script&callback=listEvents">
</script>
Exemples
Pour obtenir des exemples d'utilisation de JSON avec les API Google Data, consultez les exemples.
Ressources supplémentaires
Pour en savoir plus sur le format JSON et son utilisation dans les applications Web, nous vous recommandons de consulter plusieurs ressources externes.
Haut de page
Sauf indication contraire, le contenu de cette page est régi par une licence Creative Commons Attribution 4.0, et les échantillons de code sont régis par une licence Apache 2.0. Pour en savoir plus, consultez les Règles du site Google Developers. Java est une marque déposée d'Oracle et/ou de ses sociétés affiliées.
Dernière mise à jour le 2023/03/01 (UTC).
[[["Facile à comprendre","easyToUnderstand","thumb-up"],["J'ai pu résoudre mon problème","solvedMyProblem","thumb-up"],["Autre","otherUp","thumb-up"]],[["Il n'y a pas l'information dont j'ai besoin","missingTheInformationINeed","thumb-down"],["Trop compliqué/Trop d'étapes","tooComplicatedTooManySteps","thumb-down"],["Obsolète","outOfDate","thumb-down"],["Problème de traduction","translationIssue","thumb-down"],["Mauvais exemple/Erreur de code","samplesCodeIssue","thumb-down"],["Autre","otherDown","thumb-down"]],["Dernière mise à jour le 2023/03/01 (UTC)."],[[["\u003cp\u003eThis document explains how to use JSON with the older Google Data APIs to request and utilize data feeds.\u003c/p\u003e\n"],["\u003cp\u003eGoogle Data services can provide data in JSON format by converting XML feeds using specific rules for elements, attributes, and namespaces.\u003c/p\u003e\n"],["\u003cp\u003eTo request JSON output, use the \u003ccode\u003ealt=json\u003c/code\u003e parameter in your API request URL.\u003c/p\u003e\n"],["\u003cp\u003eFor JSON wrapped in a script tag (useful for cross-domain requests), use \u003ccode\u003ealt=json-in-script\u003c/code\u003e and a callback function with \u003ccode\u003ecallback=*functionName*\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eThe provided JavaScript example demonstrates fetching and displaying Google Calendar event data using JSON-in-script.\u003c/p\u003e\n"]]],[],null,["# Using JSON in the Google Data Protocol\n\n**Warning** : This page is about Google's older APIs, the Google Data APIs; it's relevant only to the APIs that are listed in the [Google Data APIs directory](/gdata/docs/directory), many of which have been replaced with newer APIs. For information about a specific new API, see the new API's documentation. For information about authorizing requests with a newer API, see [Google Accounts Authentication and Authorization](/accounts).\n\nThis article covers JSON as it is used within the Google Data Protocol. For more\ninformation about the protocol, view the [Developer's Guide](/gdata/docs/developers-guide).\n\nYou can use JSON with any programming language, but the examples in this document are in JavaScript.\n\nAbout JSON feeds and XML feeds\n==============================\n\nA Google Data service creates a JSON-format feed by converting the XML feed using the following rules:\n\n**Basic**\n\n- The feed is represented as a JSON object; each nested element or attribute is represented as a name/value property of the object.\n- Attributes are converted to String properties.\n- Child elements are converted to Object properties.\n- Elements that may appear more than once are converted to Array properties.\n- Text values of tags are converted to `$t` properties.\n\n**Namespace**\n\n- If an element has a namespace alias, the alias and element are concatenated using \"$\". For example, `ns:element` becomes `ns$element`.\n\n**XML**\n\n- XML version and encoding attributes are converted to version and encoding attributes of the root element, respectively.\n\nThe following example shows XML and JSON versions of the same feed. They are tabbed to provide easy comparison. \n\n### XML\n\n```\n\u003c?xml version=\"1.0\" encoding=\"UTF-8\" ?\u003e\n\u003cfeed xmlns=\"http://www.w3.org/2005/Atom\"\n xmlns:openSearch=\"http://a9.com/-/spec/opensearchrss/1.0/\"\n xmlns:gd=\"http://schemas.google.com/g/2005\"\n xmlns:gCal=\"http://schemas.google.com/gCal/2005\"\u003e\n \u003cid\u003e...\u003c/id\u003e\n \u003cupdated\u003e2006-11-12T21:25:30.000Z\u003c/updated\u003e\n \u003ctitle type=\"text\"\u003eGoogle Developer Events\u003c/title\u003e\n \u003csubtitle type=\"text\"\u003eThe calendar contains information about upcoming\n developer conferences at which Google will be speaking, along with\n other developer-related events.\u003c/subtitle\u003e\n \u003clink rel=\"http://schemas.google.com/g/2005#feed\"\n type=\"application/atom+xml\" href=\"...\" /\u003e\n \u003clink rel=\"self\" type=\"application/atom+xml\" href=\"...\" /\u003e\n \u003cauthor\u003e\n \u003cname\u003eGoogle Developer Calendar\u003c/name\u003e\n \u003cemail\u003edeveloper-calendar@google.com\u003c/email\u003e\n \u003c/author\u003e\n \u003cgenerator version=\"1.0\"\n uri=\"http://www.google.com/calendar\"\u003eGoogle Calendar\u003c/generator\u003e\n \u003copenSearch:startIndex\u003e1\u003c/openSearch:startIndex\u003e\n \u003copenSearch:itemsPerPage\u003e25\u003c/openSearch:itemsPerPage\u003e\n \u003cgCal:timezone value=\"America/Los_Angeles\" /\u003e\n \n \u003centry\u003e\n \u003cid\u003e...\u003c/id\u003e\n \u003cpublished\u003e2006-11-12T21:25:30.000Z\u003c/published\u003e\n \u003cupdated\u003e2006-11-12T21:25:30.000Z\u003c/updated\u003e\n \u003ccategory scheme=\"...\" term=\"...\" /\u003e\n \u003ctitle type=\"text\"\u003eWebmasterWorld PubCon 2006:\n Google Developer Tools in General\u003c/title\u003e\n \u003ccontent type=\"text\"\u003eGoogle is sponsoring at \n \u003ca href=\"http://www.pubcon.com/\"\u003eWebmasterWorld PubCon 2006\u003c/a\u003e. Come and\n visit us at the booth or join us for an evening demo reception where we\n will be talking \"5 ways to enhance your website with Google Code\". \n After all, it is Vegas, baby! See you soon.\u003c/content\u003e\n \u003clink rel=\"alternate\" type=\"text/html\" href=\"...\" title=\"alternate\" /\u003e\n \u003clink rel=\"self\" type=\"application/atom+xml\" href=\"...\" /\u003e\n \u003cauthor\u003e\n \u003cname\u003eGoogle Developer Calendar\u003c/name\u003e\n \u003cemail\u003edeveloper-calendar@google.com\u003c/email\u003e\n \u003c/author\u003e\n \u003cgCal:sendEventNotifications value=\"true\" /\u003e\n \u003cgd:comments\u003e\n \u003cgd:feedLink href=\"...\" /\u003e\n \u003c/gd:comments\u003e\n \u003cgd:transparency value=\"...\" /\u003e\n \u003cgd:eventStatus value=\"...\" /\u003e\n \u003cgd:where valueString=\"3150 Paradise Road, Las Vegas, NV 89109\" /\u003e\n \u003cgd:when startTime=\"2006-11-15\" endTime=\"2006-11-17\"\u003e\n \u003cgd:reminder minutes=\"10\" /\u003e\n \u003c/gd:when\u003e\n \u003c/entry\u003e\n ...\n\u003c/feed\u003e\n \n```\n\n### JSON\n\n```\n{\n \"version\": \"1.0\",\n \"encoding\": \"UTF-8\",\n \"feed\": {\n \"xmlns\": \"http://www.w3.org/2005/Atom\",\n \"xmlns$openSearch\": \"http://a9.com/-/spec/opensearchrss/1.0/\",\n \"xmlns$gd\": \"http://schemas.google.com/g/2005\",\n \"xmlns$gCal\": \"http://schemas.google.com/gCal/2005\",\n \"id\": {\"$t\": \"...\"},\n \"updated\": {\"$t\": \"2006-11-12T21:25:30.000Z\"},\n \"title\": {\n \"type\": \"text\",\n \"$t\": \"Google Developer Events\"\n },\n \"subtitle\": {\n \"type\": \"text\",\n \"$t\": \"The calendar contains information about upcoming developer \n conferences at which Google will be speaking, along with other \n developer-related events.\"\n },\n \"link\": [{\n \"rel\": \"...\",\n \"type\": \"application/atom+xml\",\n \"href\": \"...\"\n },{\n \"rel\": \"self\",\n \"type\": \"application/atom+xml\",\n \"href\": \"...\"\n }],\n \"author\": [{\n \"name\": {\"$t\": \"Google Developer Calendar\"},\n \"email\": {\"$t\": \"developer-calendar@google.com\"}\n }],\n \"generator\":{\n \"version\": \"1.0\",\n \"uri\": \"http://www.google.com/calendar\",\n \"$t\": \"Google Calendar\"\n },\n \"openSearch$startIndex\": {\"$t\": \"1\"},\n \"openSearch$itemsPerPage\": {\"$t\": \"25\"},\n \"gCal$timezone\": {\"value\": \"America/Los_Angeles\"},\n\n \"entry\": [{\n \"id\": {\"$t\": \"...\"},\n \"published\": {\"$t\": \"2006-11-12T21:25:30.000Z\"},\n \"updated\": {\"$t\": \"2006-11-12T21:25:30.000Z\"},\n \"category\": [{\n \"scheme\": \"...\",\n \"term\": \"...\"\n }],\n \"title\":{\n \"type\": \"text\",\n \"$t\": \"WebmasterWorld PubCon 2006: Google Developer Tools in General\"\n },\n \"content\": {\n \"type\": \"text\",\n \"$t\": \"Google is sponsoring at\n \u003ca href=\"http://www.pubcon.com/\"\u003eWebmasterWorld PubCon 2006\u003c/a\u003e.\n \\nCome and visit us at the booth or join us for an evening demo\n reception where we will be talking \"5 ways to enhance your website\n with Google Code\".\\nAfter all,\\nit is Vegas, baby! See you soon.\"\n },\n \"link\": [{\n \"rel\": \"alternate\",\n \"type\": \"text/html\",\n \"href\": \"...\",\n \"title\": \"alternate\"\n },{\n \"rel\": \"self\",\n \"type\": \"application/atom+xml\",\n\t \"href\": \"...\"\n }],\n \"author\": [{\n \"name\": {\"$t\": \"Google Developer Calendar\"},\n \"email\": {\"$t\": \"developer-calendar@google.com\"}\n }],\n \"gd$transparency\": {\"value\": \"http://schemas.google.com/g/2005#event.opaque\"},\n \"gd$eventStatus\": {\"value\": \"http://schemas.google.com/g/2005#event.confirmed\"},\n \"gd$comments\": {\"gd$feedLink\": {\"href\": \"...\"}},\n \"gCal$sendEventNotifications\": {\"value\": \"true\"},\n \"gd$when\": [{\n \"startTime\": \"2006-11-15\",\n \"endTime\": \"2006-11-17\",\n \"gd$reminder\": [{\"minutes\": \"10\"}]\n }],\n \"gd$where\": [{\"valueString\": \"3150 Paradise Road,Las Vegas,NV 89109\"}]},\n }]\n }\n}\n```\n\nRequesting and using JSON feeds\n===============================\n\nAtom is Google Data's default format. If you don't specify an `alt` parameter in\nyour request, then you receive an Atom feed.\n\n**Note**: The Google Data client libraries don't currently support JSON.\n\n### JSON output\n\nTo request a response in JSON format, use the `alt=json` parameter.\n\nFor example, to request Google's developer calendar feed in JSON format, send the following query: \n\n```\nhttp://www.google.com/calendar/feeds/developer-calendar@google.com/public/full?alt=json\n```\n\n### JSON-in-script output\n\nTo request a response that wraps JSON in a script tag, use the `alt=json-in-script`\nparameter and add a callback function by adding the `callback=`*functionName* parameter. \n\n```\nhttp://www.google.com/calendar/feeds/developer-calendar@google.com/public/full?alt=json-in-script&callback=myFunction\n```\n\nUsing callback functions allows you get around some of the cross-domain\nsecurity issues you might encounter in typical client side JavaScript. Usually\nbrowsers prevent you from loading files across domains because of potential\nsecurity holes and the cross domain attacks that could result.\n\nThe JSON-in-script format allows you to get around these restrictions by\nloading the response in a script tag on the client. This means that you\ncan use the response in other places in your JavaScript code on that page.\nThe JSON output is loaded when the page is loaded; no other tricks are needed.\n\nThe simple working application below demonstrates this technique: \n\n```\n\u003ch3\u003eUpcoming Google Developer Events\u003c/h3\u003e\n\n\u003cdiv id=\"agenda\"\u003e\u003c/div\u003e\n\n\u003cscript\u003e\n function listEvents(root) {\n var feed = root.feed;\n var entries = feed.entry || [];\n var html = ['\u003cul\u003e'];\n\n for (var i = 0; i \u003c entries.length; ++i) {\n var entry = entries[i];\n var title = (entry.title.type == 'html') ? entry.title.$t : escape(entry.title.$t);\n var start = (entry['gd$when']) ? entry['gd$when'][0].startTime : \"\";\t\n\n html.push('\u003cli\u003e', start, ' ', title, '\u003c/li\u003e');\n }\n\n html.push('\u003c/ul\u003e');\n document.getElementById(\"agenda\").innerHTML = html.join(\"\");\n }\n\u003c/script\u003e\n\n\u003cscript src=\"http://www.google.com/calendar/feeds/developer-calendar@google.com/public/full?alt=json-in-script&callback=listEvents\"\u003e\n\u003c/script\u003e\n```\n\nSamples\n=======\n\nFor working examples of how to use JSON with the Google Data APIs, see the [samples](/gdata/samples) page.\n\nAdditional resources\n====================\n\nThere are several external resources that you may want to check out to learn more about JSON and using JSON in web applications.\n\n- [JSON.org](http://www.json.org/)\n- [Wikipedia entry on JSON](http://en.wikipedia.org/wiki/JSON)\n- [JSON: The Fat Free Alternative\n to XML](http://www.json.org/xml.html)\n\n[Back to top](#top)"]]
