Dudes, this is so not REST

http://jens.mooseyard.com/2011/03/dudes-this-is-so-not-rest/

by mccutchen • 15 years ago

310 130 15 years ago

jens.mooseyard.com

mccutchen• 15 years ago

We might be getting close to this point: Maybe we should just give up on the term REST, since it’s become so diluted as to mean nothing more than “HTTP API that’s not as hard to use as SOAP”?

This is a shame, because RESTful APIs are (for me, anyway) usually a joy to build and to use.

mattmanser• 15 years ago

Yes, though this one's especially bad for not even bothering to use different URLs.

deno8• 15 years ago

There's already a specific term for the kind of API that rdio has: RPC. Remote Procedure Call.

I mean, come on, how can you say you have REST (with R standing for Representational) if you have section called “Methods” in your API documentation. HTTP API sounds okay, but in fact their API is not even HTTP specific (actually, it abuses HTTP).

masklinn12• 15 years ago

> We might be getting close to this point: Maybe we should just give up on the term REST, since it’s become so diluted as to mean nothing more than “HTTP API that’s not as hard to use as SOAP”?

Well except RDIO's API is not any simpler to use than SOAP.

It's RPC to and through, let's call a procedure call a procedure call.

hinathan• 15 years ago

Instead of fetishizing REST for its own sake, how about appreciating an HTTP API that can be used (read/written) with a browser via form elements and hrefs?

deno8• 15 years ago

This can be done on top of REST API with your server acting as a client to your own API. Actually, that way it'll probably be possible to implement it much safer.

And what's the use case anyway? Are you going to perform those requests from other domains and authenticating via cookies on your own? How do you protect from CSRF doing that? What's wrong with OAuth 2.0 + JS?

figure8• 15 years ago

I completely agree with you. There will always be a contingent of developers who believe enforced standards trump simplicity. As we see here, when the CORBA then SOAP crowd realized they'd lost that fight, their ilk started judging other projects by adherence to strict API structural definitions like formal "REST". That said, I do believe this constant dialog between ad-hoc simplicity and rigid standards is good for the industry; in each area, accepted practice evolves to meet the needs of its current application.

deno8• 15 years ago

REST is as simple as it gets. You could make that argument if someone were to advocate using REST outside of HTTP. But HTTP is inherently REST, so you should have a good reason to not use REST rather than the other way around.

vannevar• 15 years ago

Instead of fetishizing horses, why not appreciate this butterfly that I'm calling a horse?

http://www.youtube.com/watch?v=Sv5woNs9WRE

Being accurate with a technical term is not a 'fetish.'

mortice• 15 years ago

I once worked on a project where 'REST' was synonymous with 'putting query data into the URL before the query string', and this was done so that the webserver could cache the response.

I died a little inside every time I wrote a 'Restful' servlet there.

tariq2• 15 years ago

how about calling it RESTish? http://news.ycombinator.com/item?id=2242162

tptacek3• 15 years ago

It's not RESTish.

masklinn12• 15 years ago

How about calling it what it is, namely RPC?

wahnfrieden9• 15 years ago

Yes. The terms "RESTish" or "lower REST" are just a way to stay buzzword compliant, not actually a way of elucidating anything. They're catch-all buzzword substitutes for more accurate terms.

They're particularly bad since a strict interpretation of REST can still be valuable, yet it makes REST itself seem overly nebulous and fluffy.

People advocating terms like "RESTish" or looser definitions of REST seem to think that REST is an ultimate goal of any decent web API. It's not, REST doesn't need to be used everywhere, your API isn't crap if it's not REST. So stop calling it REST like you're embarrassed to admit it's "just" RPC.

(Sorry for ranting in reply to you -- you seem to get it)

tariq2• 15 years ago

lol whoops, forgot my sarcasm tags. i was not advocating calling anything RESTish.

billybob• 15 years ago

Or "drowsy?"

mikeryan• 15 years ago

After reading the title I was all set to come in here and complain about "REST" Nazis and make some comment about how real life situations tend to supersede strict adherence to conventions.

But then I read the article and I have to admit this is a pretty egregious break with how REST services are supposed to work.

tptacek3• 15 years ago

I came here to say the same thing. For those of you who aren't going to bother reading the Rdio API spec (I did, because there's something I want to hack together with it): the whole API is literally just a single URI that accepts a "method" param, where the method is a list of verbs like "get all tracks in this playlist" or "add a friend".

There's a case to be made for relaxing the definition of REST to accept "just a bunch of URIs" APIs that don't follow the discoverability/transparency conventions of REST. But you can't call "here's a list of verbs" a REST interface.

What you'd want to see in a Rdio REST interface would be:

* /rdio/api/1/playlists * /rdio/api/1/playlist/foo * /rdio/api/1/artist/1 * /rdio/api/1/artist/1/tracks/2

&c &c &c. But, from what I can tell, none of the state inside Rdio's database is mapped to a URI.

masklinn12• 15 years ago

> What you'd want to see in a Rdio REST interface would be:

You should disclaim that these URLs could just as well be

* /rdio?q=1&s=63

* /rdio?q=1&s=63-8

* /rdio/4E7?q=1

* /rdio/4E63?q=1

and still be part of a RESTful API.

nikcub6• 15 years ago

I don't like API version numbers in the URI.

It implies that a resource is different just because you are using a newer version of the API.

My own most recent implementations use Accept: and Content-Type to define version compatibility, which is what content negotiation is supposed to be about.

Versioning in the old web API sense meant changing the way the protocol works, and REST will always be REST and the resources will always be resources.

All that is likely to change between 'API versions' is formats, which you negotiate with headers, and adding new fields, which old clients can either ask not to get through content negotiation or can safely ignore.

pkulak• 15 years ago

I agree. I recently built an API for a project of mine and I decided to make it REST-like, but not use the HTTP method to distinguish actions. In some circumstances you can only use one (JSONP, for example), so I sacrificed some purity for "the real world". This seems like it goes a bit over the line, however.

jcromartie• 15 years ago

Actually, what the blog author is talking about is a resource-oriented architecture (ROA), which is typically implemented in a RESTful fashion over HTTP but has recently been conflated with REST itself. ROA != REST.

strmpnk2• 15 years ago

Exactly. ReST as a concept is not even tied to HTTP. HTTP's design was just heavily influenced my ReST so it happens to be good at it. Somehow people are obsessed over URL formatting and HTTP specificities... while they are important, it's not the literal embodiment of what representation state transfer is, just an implementation of it.

What most people talk about when they say REST are good HTTP practices. Meaningful URLs, proper methods, etc... are all about using HTTP properly. We can call some of these views other acronyms like ROA but it's really just appreciation for proper and modern HTTP stacks.

masklinn12• 15 years ago

> HTTP's design was just heavily influenced my ReST so it happens to be good at it.

REST was extracted from HTTP. It's not that HTTP was influenced by REST, it's the exact opposite, REST is a formalization of HTTP.

edw• 15 years ago

Thank you for calling a spade a spade! The author talks about REST being object-oriented when it is actually resource-oriented. I know I'm flirting with pedantry for getting worked up about this, but anyone who knows what "object-oriented" actually means is either lying or ignorant of the manifold meanings associated with that term.

shubber• 15 years ago

Just to amplify: there's more than a pedantic difference beteen the two. REST has a lot of serious advantages related not only to application architecture and interoperability but also to system architecture and scalability. There's a lot in the original REST dissertation about removing shared state and enabling cacheability.

The crowd that mistakes ROA for REST (I think) sees the stuff in REST that relates directly to development and gets excited - but the stuff related to making their app scale, they ignore. If you don't want to learn a little bit about everything, at least follow the rules that relate to the things you don't know about.

KevBurnsJr• 15 years ago

"we'll make the URLs pretty, but we'll ignore the stuff about statelessness."

sabat• 15 years ago

It’s object-oriented, where objects are identified by URLs

I'm not so sure that "object-oriented" is the right term here, but totally agree with the premise: this isn't REST. It's more like XML-RPC Jr.

vegashacker2• 15 years ago

Why does it matter? Ok, I agree that you probably shouldn't label something with an incorrect term, but does not having more than one URL, and not using the different HTTP methods really make a difference in terms of programmer usability?

I personally find that sometimes I have trouble spotting the "oh! I forgot to make it DELETE instead of GET" bugs. When the parameters of the API are all in the url and/or query, it feels better encapsulated.

(promise I'm not flaming, and I fully expect to get told, yes it matters, and here's why! ;)

tptacek3• 15 years ago

Yes. In this case, it makes an enormous difference. Your application can't just go to rdio/api/1/artist/whatever to look up the tracks for an artist; it has to make a SOAP-style request for the tracks for a given artist. This isn't a style nit.

vegashacker2• 15 years ago

In trying to prove you wrong and show you how easy it would be to make a similar call with the rdio API, I found out how not easy it would be to make a similar call with the rdio API. :)

masklinn12• 15 years ago

It can probably be argued to be: you can't just go to rdio/api/1/artist/whatever, but you can get the exact same thing via RPC calls.

I often think that, via REST APIs and content negotiations, API can become browseable and self-descriptive but I've yet to see any example of such a thing. Furthermore, just because an API is restful doesn't mean it's well-designed, and doesn't mean it has descriptive APIs (the artist's track could just as well be in rdio/api/64D89CAC?q=42, that wouldn't inherently make the API non-restful)

mseebach• 15 years ago

No, it's not REST, and it's stupid to call it that, but if you think that posting a few arguments makes something "SOAP-style", I find it hard to believe you've interacted with a SOAP web service recently..

Note: Requiring that the call are OAuth'ed, doesn't affect its RESTness.

masklinn12• 15 years ago

> but does not having more than one URL, and not using the different HTTP methods really make a difference in terms of programmer usability?

If you're expecting a REST API yes. It also significantly impairs the discovery and the cacheability of the API calls.

deno8• 15 years ago

HTTP makes some simple guarantees in its spec regarding to the methods used. For example, GET must never have side effects. POST, PUT, DELETE always have side effects. This simple guarantees enable software like HTTP proxies to work properly. Thus by just abiding to that simple rules your API should become cachable.

What REST brings to table is exchanging representations. For one thing, it makes your API actually simpler, since you don't even need a list of 'methods' like rdio has, all you need to know is the representations and methods stay the same—which should come natural if you know HTTP.

The other nice thing that you get for free is that it accommodates for unreliable connectivity. In case of failure you can just retry. OTOH RPC abstracts such things away. For example if you have a call like "addSomethingToList" and you retry that method, you risk having duplicates.

masklinn12• 15 years ago

> HTTP makes some simple guarantees in its spec regarding to the methods used. For example, GET must never have side effects. POST, PUT, DELETE always have side effects.

Except those are of course guidelines, the API implementor is free to entirely disregard them (much to the danger of everybody)

> For one thing, it makes your API actually simpler, since you don't actually need a list of 'methods' like rdio has, all you need to know is the representations and methods stay the same—which should be natural if you know HTTP.

Instead of a list of methods, you get a list of methods (which do not have to stay the same, by the way) and a tree of resources. Theoretically you should be able to crawl a REST API using only the document types and the root URL, I don't think I've ever seen a "public" API letting me that.

> OTOH RPC abstract such things away. For example if you have call like "addSomethingToList" and you retry that method you risk having duplicates.

Yes, because if you POST the same thing twice you don't risk fucking things up...

Oh you should be using PUT, not POST, you say? Good luck getting that one in browsers.

bobbyi• 15 years ago

GET is idempotent. It's fine if the first GET request to a resource has side effects (like creating it on demand).

rosser2• 15 years ago

GET must never have side effects. POST, PUT, DELETE always have side effects.

Pedantry: because they're supposed to be idempotent, POST, PUT, and DELETE should only have side-effects the first time they're issued against a given resource.

Also, RFC 2616 uses "SHOULD NOT", as opposed to "MUST NOT" to describe the behavior of the "safe methods". To wit, "in particular, the convention has been established that the GET and HEAD methods SHOULD NOT have the significance of taking an action other than retrieval."

wicknicks• 15 years ago

Here are some tips on how to use REST: http://www.prescod.net/rest/mistakes/ http://architects.dzone.com/news/common-rest-design-pattern

jrockway• 15 years ago

does not having more than one URL, and not using the different HTTP methods really make a difference in terms of programmer usability?

Yes. You can use libraries when the service you're trying to interact with works according to some standard.

An example: I have an app I wrote at work that is a JavaScript frontend powered by a REST API backend. The REST API tries to be a good REST citizen: proper HTTP implementation (201 + Location when something is created, 202 for "I will get to that eventually", etc.), consistent URL conventions, and a consistent data format.

The end result is an API that is easy for humans to understand, but also easy for computers to understand: the simple CRUD code was about 10 lines of backbone.js, because my API doesn't break any conventions. This means that the code to interact with it already exists, and all I had to do was make the web page look pretty.

This is a good use of programmer resources, now and in the future. In the present, I didn't have to do any work to make a pretty GUI. In the future, someone that wants to pull data from my API will not have to swear at me -- everything you can do is easily discoverable by starting from the root resource.

Hixie• 15 years ago

You can have a well-defined spec that's easy to understand without having to shoe-horn your API into HTTP's document-orientated semantics.

csears• 15 years ago

REST is now just a generic term for any HTTP API that's not SOAP. Like Xerox and Kleenex, the popular usage is technically incorrect, but in practice, it doesn't matter.

Most REST API consumers today are more like CURL than a web browser. In the CURL-like case, the RPC pattern works quite well. HATEOS and other browser-centric REST ideas often just don't fit naturally into a simple API consuming app. People need to move on.

wycats• 15 years ago

Except that there was already a perfectly good name for that: RPC. REST was defined in contrast to RPC, so calling an API that involves "POST to this URL with the method as a parameter" REST is really unnecessarily confusing.

russellperry• 15 years ago

"Like Xerox and Kleenex, the popular usage is technically incorrect, but in practice, it doesn't matter."

The integrity of some acronyms is worth defending. I wouldn't want 'ACID' diluted to mean anything less than its strict definition, and I think the same holds true for 'REST'. The benefit of these distinctions is twofold: 1) we encourage the advantages of good RESTful practices and 2) we can communicate consistently without spending unnecessary effort qualifying our meaning. If REST means 'Anything but SOAP' then at some point we'll have to come up with another shorthand for 'Real REST' or spend lots of time re-stating the principles of REST every time we need to communicate architectural strategies that use them.

I should be able to say 'Singleton' or 'MVC' or 'ACID' and know that there is enough integrity to those ideas that a competent coder will know what I mean without me having to pseudo-code or UML the concept for them. The same should hold true for REST.

masklinn12• 15 years ago

> REST is now just a generic term for any HTTP API that's not SOAP.

So you're telling me I should call my XML-RPC APIs REST?

thurn• 15 years ago

This is an increasingly common extension of the REST paradigm. Google ran into a number of problems with the restrictions of REST, so their new APIs all work this way. See their justification in this video: http://www.google.com/events/io/2010/sessions/how-google-bui...

br1• 15 years ago

Note that there's also a pdf if you don't have the time for the whole video.

deno8• 15 years ago

Those are not restrictions to REST, since REST doesn't make any specific claims about how to use things like filtering, sorting etc.

Google created GData2 as an extension to AtomPub format, which only specifies a common envelope for resources (Atom Syndication Format) and how to talk about collections of resources (AtomPub itself).

There is another notable extension to AtomPub format from Microsoft called OData.

megrimlock• 15 years ago

Slide 87 of the pdf has the best summary, but the main thing w/r/r REST is that get/put of entire resources can be too heavy.

1. custom methods let you get/put specific fields, without having to transfer the whole thing or split resources up as you add new methods.

2. custom methods avoid needing to implement complex or heavy state mutations on the client. the example was rotating an image 90 degrees; you wouldn't want to download an entire full-res image to your wimpy battery-powered phone, rotate it, and re-upload it when you can just do that on the server.

(... of course this should just update some orientation metadata instead of resampling the image -- it's just an example)

_sh• 15 years ago

As for your point 2, if you consider a REST resource as a collection of fields, you can update it without custom verbs:

  GET /resources/picture/orientation => 0
  PUT /resources/picture/orientation?value=90

REST is not so much about a simple API, but a scalable service. Custom verbs break scalability.

nikcub6• 15 years ago

I believe the issue with Rdio is not that they need custom methods, their API should just be GET, PUT, POST, DELETE, etc. but that they are passing what should be the resource as a parameter

adolph• 15 years ago

Summary:

Rdo: "Yeah, we have POST!"

Thought Palace: "What about the rest?"

extension• 15 years ago

This sort of API is not RESTful at all, regardless of whether the method name is in the HTTP header or a form variable. It's still an application-specific protocol that requires out-of-band knowledge to use. REST resources are supposed to be self-describing, which doesn't make much sense for an API like this. RPC is what is required here, so just tunnel RPC over HTTP in whatever way is most practical. And don't call it REST.

If you want a bucket of cold water over the head on this topic: http://roy.gbiv.com/untangled/2008/rest-apis-must-be-hyperte...

MatthewPhillips• 15 years ago

I've worked with APIs that return XML containing one node, which contains escaped XML. So when I read something like this it doesn't seem that bad.

wahnfrieden9• 15 years ago

That's fine. Just don't call it REST. Does buzzword compliance matter so much? Call it what it is: RPC.

hoop• 15 years ago

'''Maybe we should just give up on the term REST, since it’s become so diluted as to mean nothing more than "HTTP API that’s not as hard to use as SOAP"?'''

To be fair, I thought we were at this point already. It seems safer to assume that when one advertises a "RESTful API" they are really referring to a "REST-like" API which basically means "Hey, we don't use sessions!"

While I believe that the term is already diluted to that point, I still think it's valid to point out when people are doing it wrong.

wahnfrieden9• 15 years ago

It's diluted for sure, but it still carries a strict interpretation that is worthwhile and that some of us are still using.

My main problem with its dilution is that it's usually totally meaningless -- usually other terms like RPC or just plain old "proper HTTP" accurately describe what someone is calling REST, to there point where its supposed RESTfulness can be nothing more than for the sake of buzzword compliance.

TorKlingberg• 15 years ago

I am all with you on using GET and POST properly, but is there any REST API that actually uses PUT and DELETE?

wahnfrieden9• 15 years ago

Take a look at Sun Cloud API. It's one of the best examples.

For APIs that need regular browser support, it's fine to add fallbacks like query params to specify PUT or DELETE. But these are hacks.

whackberry• 15 years ago

FTA > In fact this is why Tim Berners-Lee used the word “method” in the HTTP protocol in the first place.

Does he have a source for this? Coincidentally I had just read the HTTP 0.9 the other day and I didn't see "method" being used that way at all. I think method, in HTTP, just means "a means to retrieve / put data", not method in the object oriented sense.

amitraman1• 15 years ago

Yes! Yes! Yes!

"HTTP API that’s not as hard to use as SOAP"

My current employer calls our API ...

... RESTful like .

davidmathers• 15 years ago

"It screams RPC. There is so much coupling on display that it should be given an X rating."

-- Roy Fielding @ http://roy.gbiv.com/untangled/2008/rest-apis-must-be-hyperte...

mkramlich• 15 years ago

So it's an HTTP-based API rather than true REST. Move on. shrug

robbles• 15 years ago

The author gives WebDAV as an example of a good standardized REST API.

Is adding new HTTP methods (like PROPFIND, MOVE, COPY, etc.) considered to be RESTful? I always thought you were supposed to structure all actions around the main 6, and add extra functionality in the data payload or query parameters.

thomasfl• 15 years ago

This is a good example of a REST anti pattern. It can be easier to understand REST, when you know what it's not.

Stormbringer• 15 years ago

In the Java world REST was pretty cool for about 18 months. And then annotations came out, and instead of all the JAX-RPC bondage and discipline, you get JAX-WS, where to make something a webservice literally all you need to do is shove the @WebService annotation on it and you are good to go†.

All the WSDL and SOAP crap gets auto-generated for you. Thereby eliminating in a single stroke REST's advantage.

Now, it is true that there is some stuff†† you can do with SOAP that you can't do with JAX-WS, but really unless you like making life difficult for yourself then don't.

Especially for a big Java to Java solution there doesn't seem to be any compelling reason to go with REST anymore. Even if everything you do maps exactly to the four SQL ops (select, update, insert, delete) it is still just as easy to use the annotation as it would be to use REST.

†C# has something similar I think.

††Example: JAX-WS is limited to what you can do with a method and parameters in Java. In your SOAP schema you can specify for instance that the array you get passed shall have between 1 and 3 members, two is okay but 4 is right out. Whereas in Java (and hence JAX-WS) if you have an Array parameter, you can't specify that it must have a certain number of elements in it.

Ingaz• 15 years ago

The simplest method of creating SOAP-services is use of SQLServer SOAP Endpoint.

Just one line for SOAP from stored procedure or function.

Is it beautiful? I don't think so. SOAP remains SOAP, ugly remains ugly.

ianloic• 15 years ago

Yep, our API isn't really technically REST in the classical use of the term. We changed some of our wording and made a blog post: http://developer.rdio.com/blog/read/No_REST_for_the_wicked

Dudes, this is so not REST

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