Versioning a RESTful API with both XML and JSON Content-Type
Solution 1
You can implement versioning either by adding a version in the content type:
application/vnd.acme.user-v1+xml
Or you can also use a qualifier in your Accept
header, that way you don’t touch your content type:
application/vnd.acme.user+xml;v=1
You can split your content type application/vnd.acme.user+xml
in two parts: the first one (application/vnd.acme.user
) describes the media type, and the second one (xml
) the format of the response. That means you can use another format like json
: application/vnd.acme.user+json
.
In the HATEOAS world, XML is better than JSON for readability and semantic purposes, if you want to use JSON, you could be interested by this specification: https://github.com/kevinswiber/siren.
Solution 2
The cleanest way I know is by using profiles. There is an IETF RFC for that (RFC 6381).
Using the accept header, indicate what type of response you expect. You can still use qualifiers as well. You can request compliance with one or more comma-separated profiles, but you must use quotes if you specify more than one profile.
Accept: application/json; profiles="http://profiles.acme.com/user/v/1"
Using the content-type header, the server can respond alike:
Content-Type: application/json; profiles="http://profiles.acme.com/user/v/1"
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PatrikAkerstrand
I'm a front end engineer at www.aftonbladet.se, Sweden's largest newspaper. Programming languages PHP JavaScript Java C# Databases Schema design MySQL, PostgreSQL Web servers Apache Frontend xhtml, html, css Prototype, JQuery, YUI3 YUI3 Grids
Updated on June 24, 2022Comments
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PatrikAkerstrand almost 2 years
According to this excellent presentation on designing RESTful interfaces, the preferred way to implement versioning is to utilize the Accept-header, using something like:
GET /products HTTP/1.1 Host: example.com Accept: application/vnd.com.myservice.v2+xml
This works perfectly for XML Content-Types, but is possible to use the same scheme for versioning the JSON-equivalent?
I.e, is it possible to ask for:
GET /products HTTP/1.1 Host: example.com Accept: application/vnd.com.myservice.v2+json
The response would be something like:
HTTP/1.1 200 OK Content-Type: application/vnd.com.myservice.v2+xml; charset=UTF-8 Allow: GET, POST <?xml version="1.0" encoding="utf-8"?> <products xmlns="urn:com.example.products" xmlns:xl="http://www.w3.org/1999/xlink"> <product id="1234" xl:type="simple" xl:href="http://example.com/products/1234"> <name>Red Stapler</name> <price currency="EUR">3.14</price> <availability>false</availability> </product> </products>
and the JSON equivalent (sort of):
HTTP/1.1 200 OK Content-Type: application/vnd.com.myservice.v2+json; charset=UTF-8 Allow: GET, POST [ { id: "1234", links: [ { rel: "self", href: "http://example.com/products/1234" } ], name: "Red Stapler", price: { currency: "EUR", value: 3.14 }, availability: false } ]
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David M almost 12 years+1 for the link to that presentation if nothing else. Thanks.
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PatrikAkerstrand almost 12 yearsThanks. When it comes to deciding between a qualifier and a new media type, which one would you prefer for versioning and why?
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William Durand almost 12 yearsI would use the qualifier to avoid modifying the content type. It's just a matter of taste I guess.