I'm wondering what REST API version defines - resource structure, URI path or both? To me, it seems that specifying version in URI like this can define both:
api.foo.com/v1/path/to/resource
While specifying version as part of mime-type:
Content-type: application/json;application,v1
Clearly defines resource representation.
Some time ago I've read that the URL of a particular resource should not change among versions. After some thinking about it makes deep sense. URL is used to define an unique resource on the internet. If you specify version in URL it makes two different resources when it comes to definition above. Such resources may be a little different (a new field was added e.g.) however they seem to be exactly the same. Since then I use only header versioning.
Its completely up to us, how we want to represent and implement API. To me also it seems that specifying version in URI defines both "Version" as well as "Resource" present in current API version or not.
Related
It is straightforward to put resource id into url if it is a int or long type. e.g.
GET files/123
But my problem is that my resource identifier is a path. e.g. /folder_1/folder_2/a.sh because the underlying implementation is a filesystem. So I can not put it as part of rest api url because it is conflict with url path.
Here's approaches what I can think of:
Put the path id as the request param. e.g.
GET files?path=/folder_1/folder_2/a.sh
Encode/decode the path to make it qualifier as part of url.
Introduce another int/long id for this resource in backend. And map it to the path. The int/long type resource id is stored in database. And I need to maintain the mapping for each CURD operation.
I am not sure whether approach 1 is restful, approach 2 needs extra encoding/decoding, and approach 3 needs extra work to maintain the mapping.
I wonder what is the best practice to design the rest api url for this kind of case.
Simple:
#GET
#Path("/files/{path:.+}")
#Produces({MediaType.TEXT_PLAIN})
public String files(
#PathParam("path") String path
) {
return path;
}
When you query files/test1/tes2 via url output is:
test1/tes2
Just put the path after a prefix, for example:
GET /files/folder_1/folder_2/a.sh
There isn't a conflict, since when the request path starts with your known prefix (/files/, in the above example), you know that the rest should be parsed as the path to the file, including any slashes.
Well, my experience designing "restful" APIs shows that you have to take into consideration future extensions of your API.
So, the guidelines work best when followed closely when it makes sense.
In your specific example, the path of the file is more of an attribute of the file, that can also serve as its unique ID.
From your API client's perspective, /files/123 would make perfect sense, but /files/dir1/file2.txt is debatable.
A query parameter here would probably help more, much like what you would do if you wanted to retrieve a filtered list of files, rather than the whole collection.
On the other hand, using a query parameter would also help for future extensions, since supporting /files/{path} would also mean conflicts when attempting to add sub-resources to your files endpoint.
For example, let's assume that you might need in the future another endpoint /files/attributes. But, having such an endpoint, would exclude any possibility for your clients to match a file named attributes.
At work, I've seen routes like this:
/people/:id/edit
But I reckon such routes are hard to build programmatically. To my mind, better, is:
/people/edit/:id
That way, you can do stuff like:
const peopleEditRoute = '/people/edit'
...
<Route path=`${peopleEditRoute}/:id`
...
<Link to=`${peopleEditRoute)/${id}`
However, a colleague commented that '/peoples/:id/edit' is more conventional - it follows REST
Are they right?
As per #jonrsharpe's comment, the route should be:
/people/:id
...for all of GET, POST, PATCH etc...
/peoples/:id/edit' is more conventional - it follows REST
Are they right?
No; REST doesn't care what spelling conventions you use for your resource identifiers.
I reckon such routes are hard to build programmatically.
They shouldn't be. URI Templates are a common solution, and I would expect library support in most languages where you are likely to be writing web code. (Hint: do you really want to be writing your own logic for deciding when to encode your data?)
One consideration for path segments is relative resolution: in particular the use of dot segments to move around an identifier hierarchy.
In other words, if you are in the context of the edit resource for some person, are you more likely to want a relative reference to another resource for the same person, or to the edit resource of a different person?
As noted by #jonrsharpe, if you are creating an API that is "of the web", then you typically will request the modification of a resource by sending a request (PATCH/POST/PUT) that identifies that resource as the request target.
The point here is cache invalidation. Caching is a constraint in the REST architectural style, and general purpose HTTP components know that responses can be re-used to service other requests, and know that successful unsafe requests invalidate previously cached responses.
I'm wondering what is the best way for my rest api uri name to include the module name that the ressource belongs to? lets clarify this, my rest api should expose the details of Object-A and should also expose the details of Object-B, in this case i can't use the ressource name ipAdresse:port/details because there is two details types.
add to this that i should not use the nesting style like this ipAdresse:port/objectA/:id/details.
So in this case, is it better to do it the following way (include the parent ressource or module name in the url):
ipAdresse:port/objecta/details
or this way (using hyphen):
ipAdresse:port/objectb-details
thanks
There's a small advantage to using path segments, if you have a family of these documents that want to link to each other
/objecta/details
/objecta/comments
/objecta/pricing
These resources can all reference each other using dot segments (ex: ../comments), which means that you don't have to specify the "objecta" part in the links. In other words, you could move the whole family of identifiers to a different location in your hierarchy, and relative resolution would just work.
/objectb-details
/objectb-comments
/objectb-pricing
Each of these paths is a single segment, so dot segments remove the entire path, which you would have to replace (ex: ../objectb-comment), and if you decide to replace the objectb prefix with something else, you also need to update all of the links.
In effect, using / gives you a little bit of future proofing.
That said, if the hyphen-minus is part of the name of the thing, then leave it in the identifier.
/objective-c/comments
If you bring one of these to me in a code review, I'm going to think you've lost the plot:
/objective/c/comments
/objective-c-comments
But of course they will work just as well (the machines don't care) as long as the identifiers match the syntax described by RFC 3986.
I am creating HTTP request using Apache HTTP Client version 4.3.4. I see there are some classes like HttpGet,... and there is also a class BasicHttpRequest. I am not sure which one to use.
Whats the difference and which one should be used in which condition ?
BasicHttpRequest is provided by the core library. As its name suggests it is pretty basic: it enforces no particular method name or type, nor does it attempt to validate the request URI. The URI parameter can be any arbitrary garbage. HttpClient will dutifully transmit it to server as is, if it is unable to parse it to a valid URI.
HttpUriRequest variety on the other hand will enforce specific method type and will require a valid URI. Another important feature is that HttpUriRequest can be aborted at any point of their execution.
You should always be using classes that implement HttpUriRequest per default.
I was just browsing the 4.3.6 javadoc attempting to locate your BasicHttpRequest and was unable to find it. Do you have a reference to the javadoc of this class?
I would be under the impression that BasicHttpRequest would be a base class providing operations and attributes common to more than one HttpRequest. It may be extremely generic for extension purposes.
To the first part of your question, use HttpGet, HttpPost etc for their specific operations. If you only need to HTTP/GET information then use HttpGet, if you need to post a form or document body, then use HttpPost. If you are attempting to use things like the Head, Put, Delete method, then use the correspoding HttpXXX class.
What is the best way to version REST URIs? Currently we have a version # in the URI itself, ie.
http://example.com/users/v4/1234/
for version 4 of this representation.
Does the version belong in the queryString? ie.
http://example.com/users/1234?version=4
Or is versioning best accomplished another way?
Do not version URLs, because ...
you break permalinks
The url changes will spread like a disease through your interface. What do you do with representations that have not changed but point to the representation that has? If you change the url, you break old clients. If you leave the url, your new clients may not work.
Versioning media types is a much more flexible solution.
Assuming that your resource is returning some variant of application/vnd.yourcompany.user+xml all you need to do is create support for a new application/vnd.yourcompany.userV2+xml media type and through the magic of content negotiation your v1 and v2 clients can co-exist peacefully.
In a RESTful interface, the closest thing you have to a contract is the definition of the media-types that are exchanged between the client and the server.
The URLs that the client uses to interact with the server should be provided by the server embedded in previously retrieved representations. The only URL that needs to be known by the client is the root URL of the interface. Adding version numbers to urls only has value if you construct urls on the client, which you are not suppose to do with a RESTful interface.
If you need to make a change to your media-types that will break your existing clients then create a new one and leave your urls alone!
And for those readers currently saying that this makes no sense if I am using application/xml and application/json as media-types. How are we supposed to version those? You're not. Those media-types are pretty much useless to a RESTful interface unless you parse them using code-download, at which point versioning is a moot point.
I would say making it part of the URI itself (option 1) is best because v4 identifies a different resource than v3. Query parameters like in your second option can be best used to pass-in additional (query) info related to the request, rather than the resource.
Ah, I'm putting my old grumpy hat on again.
From a ReST perspective, it doesn't matter at all. Not a sausage.
The client receives a URI it wants to follow, and treats it as an opaque string. Put whatever you want in it, the client has no knowledge of such a thing as a version identifier on it.
What the client knows is that it can process the media type, and I'll advise to follow Darrel's advice. Also I personally feel that needing to change the format used in a restful architecture 4 times should bring huge massive warning signs that you're doing something seriously wrong, and completely bypassing the need to design your media type for change resiliance.
But either way, the client can only process a document with a format it can understand, and follow links in it. It should know about the link relationships (the transitions). So what's in the URI is completely irrelevant.
I personally would vote for http://localhost/3f3405d5-5984-4683-bf26-aca186d21c04
A perfectly valid identifier that will prevent any further client developer or person touching the system to question if one should put v4 at the beginning or at the end of a URI (and I suggest that, from the server perspective, you shouldn't have 4 versions, but 4 media types).
You should NOT put the version in the URL, you should put the version in the Accept Header of the request - see my post on this thread:
Best practices for API versioning?
If you start sticking versions in the URL you end up with silly URLs like this:
http://company.com/api/v3.0/customer/123/v2.0/orders/4321/
And there are a bunch of other problems that creep in as well - see my blog:
http://thereisnorightway.blogspot.com/2011/02/versioning-and-types-in-resthttp-api.html
These (less-specific) SO questions about REST API versioning may be helpful:
Versioning RESTful services?
Best practices for web service REST API versioning
There are 4 different approaches to versioning the API:
Adding version to the URI path:
http://example.com/api/v1/foo
http://example.com/api/v2/foo
When you have breaking change, you must increment the version like: v1, v2, v3...
You can implement a controller in you code like this:
#RestController
public class FooVersioningController {
#GetMapping("v1/foo")
public FooV1 fooV1() {
return new FooV1("firstname lastname");
}
#GetMapping("v2/foo")
public FooV2 fooV2() {
return new FooV2(new Name("firstname", "lastname"));
}
Request parameter versioning:
http://example.com/api/v2/foo/param?version=1
http://example.com/api/v2/foo/param?version=2
The version parameter can be optional or required depending on how you want the API to be used.
The implementation can be similar to this:
#GetMapping(value = "/foo/param", params = "version=1")
public FooV1 paramV1() {
return new FooV1("firstname lastname");
}
#GetMapping(value = "/foo/param", params = "version=2")
public FooV2 paramV2() {
return new FooV2(new Name("firstname", "lastname"));
}
Passing a custom header:
http://localhost:8080/foo/produces
With header:
headers[Accept=application/vnd.company.app-v1+json]
or:
headers[Accept=application/vnd.company.app-v2+json]
Largest advantage of this scheme is mostly semantics: You aren’t cluttering the URI with anything to do with the versioning.
Possible implementation:
#GetMapping(value = "/foo/produces", produces = "application/vnd.company.app-v1+json")
public FooV1 producesV1() {
return new FooV1("firstname lastname");
}
#GetMapping(value = "/foo/produces", produces = "application/vnd.company.app-v2+json")
public FooV2 producesV2() {
return new FooV2(new Name("firstname", "lastname"));
}
Changing Hostnames or using API Gateways:
Essentially, you’re moving the API from one hostname to another. You might even just call this building a new API to the same resources.
Also,you can do this using API Gateways.
I wanted to create versioned APIs and I found this article very useful:
http://blog.steveklabnik.com/posts/2011-07-03-nobody-understands-rest-or-http
There is a small section on "I want my API to be versioned". I found it simple and easy to understand. The crux is to use Accept field in the header to pass version information.
If the REST services require authentication before use, you could easily associate the API key/token with an API version and do the routing internally. To use a new version of the API, a new API key could be required, linked to that version.
Unfortunately, this solution only works for auth-based APIs. However, it does keep versions out of the URIs.
If you use URIs for versioning, then the version number should be in the URI of the API root, so every resource identifier can include it.
Technically a REST API does not break by URL changes (the result of the uniform interface constraint). It breaks only when the related semantics (for example an API specific RDF vocab) changes in a non backward compatible way (rare). Currently a lot of ppl do not use links for navigation (HATEOAS constraint) and vocabs to annotate their REST responses (self-descriptive message constraint) that's why their clients break.
Custom MIME types and MIME type versioning does not help, because putting the related metadata and the structure of the representation into a short string does not work. Ofc. the metadata and the structure will frequently change, and so the version number too...
So to answer your question the best way to annotate your requests and responses with vocabs (Hydra, linked data) and forget versioning or use it only by non backward compatible vocab changes (for example if you want to replace a vocab with another one).
I'd include the version as an optional value at the end of the URI. This could be a suffix like /V4 or a query parameter like you've described. You might even redirect the /V4 to the query parameter so you support both variations.
I vote up for doing this in mime type but not in URL.
But the reason is not the same as other guys.
I think the URL should be unique (excepting those redirects) for locating the unique resource.
So, if you accept /v2.0 in URLs, why it is not /ver2.0 or /v2/ or /v2.0.0? Or even -alpha and -beta? (then it totally becomes the concept of semver)
So, the version in mime type is more acceptable than the URL.