Short version of the question:
Does "GET" at a particular URI need to match what was "PUT" to that URI?
I think not. Here's why:
Given that a resource is an abstract thing that is theoretically unknowable by the client, when we do a PUT, we must be only sending a representation. Based on combing over RFC2616, it doesn't seem entirely specified as to what that means for a resource that has many (potentially infinite?) representations, but here are my thoughts; please tell me if you agree:
My expectation is that if I PUT a representation to a resource, all other representations of the resource at that URI should be kept consistent (potentially updated) as necessary. In other words, you're telling the resource "use this representation to redefine yourself".
Thus, I should be able to do this:
PUT /resources/foo/myvacation
Content-type: image/jpg
...
And follow up with this:
GET /resources/foo/myvacation
Accept: image/png
...
and get the updated version of myvacation in a different format (assuming the server knows how to do that). Extrapolating from that, this composite atomic "image + metadata" PUT should also be legal:
PUT /resources/foo/myvacation
Content-type: multipart/form-data
Content-disposition: form-data; name="document"
Content-type: image/jpg
[..]
Content-disposition: form-data; name="iptc"
Content-type: application/iptc
[..]
Content-disposition: form-data; name="exif"
Content-type: application/exif
[..]
And then, because server-side content negotiation (RFC2616 section 12.1) can take place based on just about anything, we can default to the "document" content for this:
GET /resources/foo/myvacation
Content-type: image/jpg
[..]
or if you believe as I do that RFC 2396 section 3.4 "The query component is a string of information to be interpreted by the resource." means that a URI with a query string refers to the same resource as a URI without a query string (and is isomorphic with just sending application/x-form-urlencoded data to the resource), then this should also be legal:
GET /resources/foo/myvacation?content=exif
Content-type: application/exif
[..]
The description of PUT says:
The PUT method requests that the enclosed entity be stored under the supplied Request-URI.
To me, this is fairly anti-REST, unless you read it in a very liberal manner. My interpretation is "The PUT method requests that a resource be created or updated at the supplied Request-URI based on the representation of the enclosed entity."
Later on, we get:
The fundamental difference between the POST and PUT requests is reflected in the different meaning of the Request-URI. The URI in a POST request identifies the resource that will handle the enclosed entity. That resource might be a data-accepting process, a gateway to some other protocol, or a separate entity that accepts annotations. In contrast, the URI in a PUT request identifies the entity enclosed with the request -- the user agent knows what URI is intended and the server MUST NOT attempt to apply the request to some other resource.
We need to similarly read this creatively, but the key bits here are "knows what URI is intended" and "apply the request".
So, to me the representation returned by GET at a given URI does not necessarily have to be the same representation that was PUT to the given URI, it just has to be consistent.
True or false?
Based on the fact that content negotiation can return different representations from the same URI, I am quite sure that what you PUT does not have to be the same as what you retrieve.
Your assumptions are correct. The GET doesn't necessarily have to return the same representation as what you PUT, but it does have to be the same resource.
I'm currently working on a web application that will return any resource as XHTML, JSON, or a custom XML dialect, depending on what you ask for in the content negotiation headers. So a browser will see the HTML by default. Other HTTP clients, including XMLHttpRequest, can get the JSON, and so on. They are all representations of the same resource at the same URI.
Likewise, our application will accept a PUT or POST in any of the supported formats (subject to the semantics of the particular resource or collection in question.)
I agree with the other answers that resource that you PUT is not required to be the same as the one that you later GET. I wanted to add some of my experience to this question around this area.
You need to be very careful when relying on content-negotiation. It is very tricky to get right and if you don't get it right leads to nasty user problems. Let's do an example based on images...
If Alice PUTs an image in a raw format, then Bob can GET the image as a jpeg(through a server side raw->jpeg transform), and Alice can GET the image in a raw format; No problems. However, if Bob PUTs a jpeg, then there is no way to get back to the raw format for Alice. In the case of vacation photos the lack of symmetric transforms may not be a big deal, but in medical images it would be.
Another area where the lack of symmetric transforms bites you is in representations where one has a schema and the other does not. In this case, on the server side you end up making conventions for how to transform between them. But you get into big problems when you are dealing with documents with schemas that change over time and are out of your control. Everytime the schema changes you have to update all of your transforms for the new schema shape, while still supporting resources using the old schema. Content negotiation quickly becomes more trouble than its worth except for a few limited circumstances. One of the areas where it can be manageable is if you fully control the resource representation and its underlying schema. Another area is if the resource formats are standards and its possible to make symmetric transformations between the different formats.
If you are transforming then it would make sense that what you PUT is not what you GET, so I don't see why it is a problem.
But, if you PUT a user with certain information, then when you use GET then it should retrieve that person, just as, when I put my 4th vacation photo, when I call GET I expect that photo, but it may be transformed by converting to a different format, or have some other transforms, but, if I get the 5th photo instead, then that is a problem.
Related
I'm writing a REST web service that translates texts from one language to another. The text can be fairly large, up to a few megabytes.
What HTTP verb is best to use?
My first thought was to use GET because it gets you the translation for the given text. But the 4K URL length restriction will not do for large texts. The use of the message body with GET is discouraged.
My second thought was to use POST so I can pass the text in the request body. But it doesn't seem to agree with the spirit of HTTP. POST is used to create things; it updates the state of the server while in my case no state is being updated.
What verb would you use?
N.B. Google Translate uses POST.
I'm learning towards POST, as i see PUT, PATCH, DELETE etc. as specific options.
GET would be the 'appropriate', as its origin is "GET a given resource", eg. fetch my a translation, based on some data you parse along.
However I believe it can be argued, that the translation does not exist, but is merely generated, therefore you POST your string, and the webservice creates the translations, and returns it. Also, as you mention, GET requests are blocked by the URL Length.
Should the HEAD and GET methods return the same status code? More specifically, we have run into the situation where a client website is returning a 200 when we do a HEAD, but returns a 303 when we do a GET. It has to do with redirecting to a language specific page based on location, but shouldn't the HEAD then also ask you to redirect?
but shouldn't the HEAD then also ask you to redirect?
The key is the word SHOULD. From the HTTP method specification, RFC9110:
9.3.2 HEAD
The HEAD method is identical to GET except that the server MUST NOT send content in the response. HEAD is used to obtain metadata about the selected representation without transferring its representation data, often for the sake of testing hypertext links or finding recent modifications.
The server SHOULD send the same header fields in response to a HEAD request as it would have sent if the request method had been GET. However, a server MAY omit header fields for which a value is determined only while generating the content..
The word SHOULD is further definied in RFC2119:
SHOULD This word, or the adjective "RECOMMENDED", mean that there
may exist valid reasons in particular circumstances to ignore a
particular item, but the full implications must be understood and
carefully weighed before choosing a different course.
So, the case you described is legit, but not recommended. You may want to ask the site maintainer for the reasoning of this path.
While the HTTP 1.1 spec seems to allow message bodies on DELETE requests, it seems to indicate that servers should ignore it since there are no defined semantics for it.
4.3 Message Body
A server SHOULD read and forward a message-body on any request; if the
request method does not include defined semantics for an entity-body,
then the message-body SHOULD be ignored when handling the request.
I've already reviewed several related discussions on this topic on SO and beyond, such as:
Is an entity body allowed for an HTTP DELETE request?
Payloads of HTTP Request Methods
HTTP GET with request body
Most discussions seem to concur that providing a message body on a DELETE may be allowed, but is generally not recommended.
Further, I've noticed a trend in various HTTP client libraries where more and more enhancements seem to be getting logged for these libraries to support request bodies on DELETE. Most libraries seem to oblige, although occasionally with a little bit of initial resistance.
My use case calls for the addition of some required metadata on a DELETE (e.g. the "reason" for deletion, along with some other metadata required for deletion). I've considered the following options, none of which seem completely appropriate and inline with HTTP specs and/or REST best practices:
Message Body - The spec indicates that message bodies on DELETE have no semantic value; not fully supported by HTTP clients; not standard practice
Custom HTTP Headers - Requiring custom headers is generally against standard practices; using them is inconsistent with the rest of my API, none of which require custom headers; further, no good HTTP response available to indicate bad custom header values (probably a separate question altogether)
Standard HTTP Headers - No standard headers are appropriate
Query Parameters - Adding query params actually changes the Request-URI being deleted; against standard practices
POST Method - (e.g. POST /resourceToDelete { deletemetadata }) POST is not a semantic option for deleting; POST actually represents the opposite action desired (i.e. POST creates resource subordinates; but I need to delete the resource)
Multiple Methods - Splitting the DELETE request into two operations (e.g. PUT delete metadata, then DELETE) splits an atomic operation into two, potentially leaving an inconsistent state. The delete reason (and other related metadata) are not part of the resource representation itself.
My first preference would probably be to use the message body, second to custom HTTP headers; however, as indicated, there are some downsides to these approaches.
Are there any recommendations or best practices inline with REST/HTTP standards for including such required metadata on DELETE requests? Are there any other alternatives that I haven't considered?
Despite some recommendations not to use the message body for DELETE requests, this approach may be appropriate in certain use cases. This is the approach we ended up using after evaluating the other options mentioned in the question/answers, and after collaborating with consumers of the service.
While the use of the message body is not ideal, none of the other options were perfectly fitting either. The request body DELETE allowed us to easily and clearly add semantics around additional data/metadata that was needed to accompany the DELETE operation.
I'd still be open to other thoughts and discussions, but wanted to close the loop on this question. I appreciate everyone's thoughts and discussions on this topic!
Given the situation you have, I would take one of the following approaches:
Send a PUT or PATCH: I am deducing that the delete operation is virtual, by the nature of needing a delete reason. Therefore, I believe updating the record via a PUT/PATCH operation is a valid approach, even though it is not a DELETE operation per se.
Use the query parameters: The resource uri is not being changed. I actually think this is also a valid approach. The question you linked was talking about not allowing the delete if the query parameter was missing. In your case, I would just have a default reason if the reason is not specified in the query string. The resource will still be resource/:id. You can make it discoverable with Link headers on the resource for each reason (with a rel tag on each to identify the reason).
Use a separate endpoint per reason: Using a url like resource/:id/canceled. This does actually change the Request-URI and is definitely not RESTful. Again, link headers can make this discoverable.
Remember that REST is not law or dogma. Think of it more as guidance. So, when it makes sense to not follow the guidance for your problem domain, don't. Just make sure your API consumers are informed of the variance.
What you seem to want is one of two things, neither of which are a pure DELETE:
You have two operations, a PUT of the delete reason followed by a DELETE of the resource. Once deleted, the contents of the resource are no longer accessible to anyone. The 'reason' cannot contain a hyperlink to the deleted resource. Or,
You are trying to alter a resource from state=active to state=deleted by using the DELETE method. Resources with state=deleted are ignored by your main API but might still be readable to an admin or someone with database access. This is permitted - DELETE doesn't have to erase the backing data for a resource, only to remove the resource exposed at that URI.
Any operation which requires a message body on a DELETE request can be broken down into at it's most general, a POST to do all the necessary tasks with the message body, and a DELETE. I see no reason to break the semantics of HTTP.
I suggest you include the required metadata as part of the URI hierarchy itself. An example (Naive):
If you need to delete entries based on a date range, instead of passing the start date and end date in body or as query parameters, structure the URI such a way that you pass the required information as part of the URI.
e.g.
DELETE /entries/range/01012012/31122012 -- Delete all entries between 01 January 2012 to 31st December 2012
Hope this helps.
I would say that query parameters are part of the resource definition, thus you can use them to define the scope of your operation, then "apply" the operation.
My conclusion is that Query Parameters as you defined it is the best approach.
I have REST services which should receive really long queries via GET. Say for example I want to query a service with many geographical coordinates to find out something about all this coordinates.
1) My first thought was to use long URIs and increase the max URI length of the servlet container.
It would look like this:
GET http://some.test/myresource?query={really big JSON object}
But it seems that URIs longer than 2 KB are not reliable due to old proxy servers (is that right?).
2) My workaround is to create a temporary resource via POST first and use the URI of this resource as parameter in the actual GET request. That would look like this:
POST http://some.test/temp
Request Body: {really big JSON object}
201 Created Location: http://some.test/temp/12309871
GET http://some.test/myresource?query=http://some.test/temp/12309871
3) Use body of GET request. I've read the answers to the question whether it is a good idea to use the body of a GET request for the query, and the consensus is: no. Even Roy Fielding says that this is a bad idea.
4) Another approach could be to interpret POST as "create query result resource" and delete this resource after the request. But I consider that to be not RESTful and to be a bad idea.
Is there a better way to handle big queries with GET requests?
Use PUT.
Why? For the following reasons:
Just because the verb PUT 'may update' the resource, doesn't mean it will or must alter underlying state of the resource.
No new resource identifier (url) should be created by the API side of a PUT. Yes, technically a PUT with a client specified identifier is possible, but in this case you're hitting an existing resource.
PUT is like GET in the fact that it should be idempotent, meaning the results of the request will always be the same regardless of how often you call it and it has no side effects.
PUT means you're putting resource data to an existing resource. In terms of a article or post in the document / blog post worlds, it would be like uploading a new revision of some document to an existing resource URL. If you upload the same revision to the same URL, nothing should change in the resource you get back.
In your case, the geo data is some new resource data you're uploading and the result you get back should be the same every time you make the same request.
A more purist method to use the GET verb for the request might be:
Create an endpoint for a query resource type
POST the JSON set of query details to a query resource endpoint and get an identifier for the query resource (say it returns a query id of 123)
Submit to the get request a query identifier http://some.test/myresource?query_id=123
Delete the query resource 123
I see the pure method much more overhead than using PUT with query resource data in the body.
I thought that the whole point in REST was to work on "documents" (or something alike). The URI part of a request is there to identify uniquely the resource to work on. The body part in contrast is there for the "contents" part of the document.
Hence, use the "body" part of the request.
Also note that the semantics of a "GET" request isn't supposed to be used for "PUTTING" or "POSTING" documents (comment in relation to your "query" example above which seems to "create" an object).
In any case, as you have pointed out, the URI part is limited (for good reason I am sure).
If you are concerned with caching, then the use of ETag/Last-Modified fields (in conjunction with "conditional GET" helps for this purpose.
Here is a slight variation on your second option. Create yourself a processor resource called QueryMaker. POST your parameters to it and let it redirect you to a temporary query resource that will return your results.
POST /QueryMaker
Body: Big Json representation of parameters
303: See Other
Location: http://example.org/TemporaryQueries/123213
If you are using a GET request to send large objects, you are not using REST correctly.
GET should be used for retrieving
resources (via some sort of unique
identifier)
POST should be used for
creating resources (with the contents
in the body)
PUT should be used for
updating a resource (with the
contents in the body)
DELETE should be used for deleting a resource
If you follow these guidelines you will never have to have overly long URIs.
Some best practice REST guidelines are here: http://www.xml.com/pub/a/2004/08/11/rest.html
The biggest limitation of URL lengths on the open Web is actually IE, which constraints them to 2083 characters.
Some proxies (e.g., all but the most recent versions of Squid) will limit them to about 4k, although this is moving towards 8k slowly.
Your #2 workaround is a good approach, depending on your use case.
Sending bodies on GETs may be allowed by some implementations, and disallowed by others, so it's a bad idea for interoperability as well as theoretical reasons. Most importantly, how will a cache know what to use as a key?
Can't you just send the big JSON data with the GET request body, instead of creating the temp resource?
Although it's not 100% kosher, i've found it works nicely with firefox and IE and IMO, the querystring is inelegant and usually exposes implementation details that don't belong in the URI. Just make sure to add a cache buster querystring parameter if you need up-to-date data because the server will ignore the data when determining whether it can return a cached response.
See here for a discussion of pros and cons of stuffing data in the GET request body.
I'm interested in exposing a direct REST interface to collections of JSON documents (think CouchDB or Persevere). The problem I'm running into is how to handle the GET operation on the collection root if the collection is large.
As an example pretend I'm exposing StackOverflow's Questions table where each row is exposed as a document (not that there necessarily is such a table, just a concrete example of a sizable collection of 'documents'). The collection would be made available at /db/questions with the usual CRUD api GET /db/questions/XXX, PUT /db/questions/XXX, POST /db/questions is in play. The standard way to get the entire collection is to GET /db/questions but if that naively dumps each row as a JSON object, you'll get a rather sizeable download and a lot of work on the part of the server.
The solution is, of course, paging. Dojo has solved this problem in its JsonRestStore via a clever RFC2616-compliant extension of using the Range header with a custom range unit items. The result is a 206 Partial Content that returns only the requested range. The advantage of this approach over a query parameter is that it leaves the query string for...queries (e.g. GET /db/questions/?score>200 or somesuch, and yes that'd be encoded %3E).
This approach completely covers the behavior I want. The problem is that RFC 2616 specifies that on a 206 response (emphasis mine):
The request MUST have included a Range header field (section 14.35)
indicating the desired range, and MAY have included an If-Range
header field (section 14.27) to make the request conditional.
This makes sense in the context of the standard usage of the header but is a problem because I'd like the 206 response to be the default to handle naive clients/random people exploring.
I've gone over the RFC in detail looking for a solution but have been unhappy with my solutions and am interested in SO's take on the problem.
Ideas I've had:
Return 200 with a Content-Range header! - I don't think that this is wrong, but I'd prefer if a more obvious indicator that the response is only Partial Content.
Return 400 Range Required - There is not a special 400 response code for required headers, so the default error has to be used and read by hand. This also makes exploration via web browser (or some other client like Resty) more difficult.
Use a query parameter - The standard approach, but I'm hoping to allow queries a la Persevere and this cuts into the query namespace.
Just return 206! - I think most clients wouldn't freak out, but I'd rather not go against a MUST in the RFC
Extend the spec! Return 266 Partial Content - Behaves exactly like 206 but is in response to a request that MUST NOT contain the Range header. I figure that 266 is high enough that I shouldn't run into collision issues and it makes sense to me but I'm not clear on whether this is considered taboo or not.
I'd think this is a fairly common problem and I'd like to see this done in a sort of de facto fashion so I or someone else isn't reinventing the wheel.
What's the best way to expose a full collection via HTTP when the collection is large?
I don't really agree with some of you guys. I've been working for weeks on this features for my REST service. What I ended up doing is really simple. My solution only makes a sense for what REST people call a collection.
Client MUST include a "Range" header to indicate which part of the collection he needs, or otherwise be ready to handle a 413 REQUESTED ENTITY TOO LARGE error when the requested collection is too large to be retrieved in a single round-trip.
Server sends a 206 PARTIAL CONTENT response, with the Content-Range header specifying which part of the resource has been sent, and an ETag header to identify the current version of the collection. I usually use a Facebook-like ETag {last_modification_timestamp}-{resource_id}, and I consider that the ETag of a collection is that of the most recently modified resource it contains.
To request a specific part of a collection, the client MUST use the "Range" header, and fill the "If-Match" header with the ETag of the collection obtained from previously performed requests to acquire other parts of the same collection. The server can therefore verify that the collection hasn't changed before sending the requested portion. If a more recent version exists, a 412 PRECONDITION FAILED response is returned to invite the client to retrieve the collection from scratch. This is necessary because it could mean that some resources might have been added or removed before or after the currently requested part.
I use ETag/If-Match in tandem with Last-Modified/If-Unmodified-Since to optimize cache. Browsers and proxies might rely on one or both of them for their caching algorithms.
I think that a URL should be clean unless it's to include a search/filter query. If you think about it, a search is nothing more than a partial view of a collection. Instead of the cars/search?q=BMW type of URLs, we should see more cars?manufacturer=BMW.
My gut feeling is that the HTTP range extensions aren't designed for your use case, and thus you shouldn't try. A partial response implies 206, and 206 must only be sent if the client asked for it.
You may want to consider a different approach, such as the one use in Atom (where the representation by design may be partial, and is returned with a status 200, and potentially paging links). See RFC 4287 and RFC 5005.
You can still return Accept-Ranges and Content-Ranges with a 200 response code. These two response headers give you enough information to infer the same information that a 206 response code provides explicitly.
I would use Range for pagination, and have it simply return a 200 for a plain GET.
This feels 100% RESTful and doesn't make browsing any more difficult.
Edit:
I wrote a blog post about this: http://otac0n.com/blog/2012/11/21/range-header-i-choose-you.html
If there is more than one page of responses, and you don't want to offer the whole collection at once, does that mean there are multiple choices?
On a request to /db/questions, return 300 Multiple Choices with Link headers that specify how to get to each page as well as a JSON object or HTML page with a list of URLs.
Link: <>; rel="http://paged.collection.example/relation/paged"
Link: <>; rel="http://paged.collection.example/relation/paged"
...
You'd have one Link header for each page of results (an empty string means the current URL, and the URL is the same for each page, just accessed with different ranges), and the relationship is defined as a custom one per the upcoming Link spec. This relationship would explain your custom 266, or your violation of 206. These headers are your machine-readable version, since all of your examples require an understanding client anyway.
(If you stick with the "range" route, I believe your own 2xx return code, as you described it, would be the best behavior here. You're expected to do this for your applications and such ["HTTP status codes are extensible."], and you have good reasons.)
300 Multiple Choices says you SHOULD also provide a body with a way for the user agent to pick. If your client is understanding, it should use the Link headers. If it's a user manually browsing, perhaps an HTML page with links to a special "paged" root resource that can handle rendering that particular page based on the URL? /humanpage/1/db/questions or something hideous like that?
The comments on Richard Levasseur's post remind me of an additional option: the Accept header (section 14.1). Back when the oEmbed spec came out, I wondered why it hadn't been done entirely using HTTP, and wrote up an alternative using them.
Keep the 300 Multiple Choices, the Link headers and the HTML page for an initial naive HTTP GET, but rather than use ranges, have your new paging relationship define the use of the Accept header. Your subsequent HTTP request might look like this:
GET /db/questions HTTP/1.1
Host: paged.collection.example
Accept: application/json;PagingSpec=1.0;page=1
The Accept header allows you to define an acceptable content type (your JSON return), plus extensible parameters for that type (your page number). Riffing on my notes from my oEmbed writeup (can't link to it here, I'll list it in my profile), you could be very explicit and provide a spec/relation version here in case you need to redefine what the page parameter means in the future.
Edit:
After thinking about it a bit more, I'm inclined to agree that Range headers aren't appropriate for pagination. The logic being, the Range header is intended for the server's response, not the applications. If you served 100 megabytes of results, but the server (or client) could only process 1 megabyte at a time, well, thats what the Range header is for.
I'm also of the opinion that a subset of resources is its own resource (similar to relational algebra.), so it deserve representation in the URL.
So basically, I recant my original answer (below) about using a header.
I think you answered your own question, more or less - return 200 or 206 with content-range and optionally use a query parameter. I would sniff the user agent and content type and, depending on those, check for a query parameter. Otherwise, require the range headers.
You essentially have conflicting goals - let people use their browser to explore (which doesn't easily allow custom headers), or force people to use a special client that can set headers (which doesn't let them explore).
You could just provide them with the special client depending on the request - if it looks like a plain browser, send down a small ajax app that renders the page and sets the necessary headers.
Of course, there is also the debate about whether the URL should contain all the necessary state for this sort of thing. Specifying the range using headers can be considered "un-restful" by some.
As an aside, it would be nice if servers could respond with a "Can-Specify: Header1, header2" header, and web browsers would present a UI so users could fill in values, if they desired.
You might consider using a model something like the Atom Feed Protocol since it has a sane HTTP model of collections and how to manipulate them (where insane means WebDAV).
There's the Atom Publishing Protocol which defines the collection model and REST operations plus you can use RFC 5005 - Feed Paging and Archiving to page through big collections.
Switching from Atom XML to JSON content should not affect the idea.
I think the real problem here is that there is nothing in the spec that tells us how to do automatic redirects when faced with 413 - Requested Entity Too Large.
I was struggling with this same problem recently and I looked for inspiration in the RESTful Web Services book. Personally I don't think 206 is appropriate due to the header requirement. My thoughts also led me to 300, but I thought that was more for different mime-types, so I looked up what Richardson and Ruby had to say on the subject in Appendix B, page 377. They suggest that the server just pick the preferred representation and send it back with a 200, basically ignoring the notion that it should be a 300.
That also jibes with the notion of links to next resources that we have from atom. The solution I implemented was to add "next" and "previous" keys to the json map I was sending back and be done with it.
Later on I started thinking maybe the thing to do is send a 307 - Temporary Redirect to a link that would be something like /db/questions/1,25 - that leaves the original URI as the canonical resource name, but it gets you to an appropriately named subordinate resource. This is behavior I'd like to see out of a 413, but 307 seems a good compromise. Haven't actually tried this in code yet though. What would be even better is for the redirect to redirect to a URL containing the actual IDs of the most recently asked questions. For example if each question has an integer ID, and there are 100 questions in the system and you want to show the ten most recent, requests to /db/questions should be 307'd to /db/questions/100,91
This is a very good question, thanks for asking it. You confirmed for me that I'm not nuts for having spent days thinking about it.
One of the big problems with range headers is that a lot of corporate proxies filter them out. I'd advise to use a query parameter instead.
With the publication of rfc723x, unregistered range units do go against an explicit recommendation in the spec. Consider rfc7233 (deprecating rfc2616):
"New range units ought to be registered with IANA" (along with a reference to a HTTP Range Unit Registry).
You can detect the Range header, and mimic Dojo if it is present, and mimic Atom if it is not. It seems to me that this neatly divides the use cases. If you are responding to a REST query from your application, you expect it to be formatted with a Range header. If you are responding to a casual browser, then if you return paging links it will let the tool provide an easy way to explore the collection.
Seems to me that the best way to do this is to include range as query parameters. e.g., GET /db/questions/?date>mindate&date<maxdate. Upon a GET to the /db/questions/ with no query parameters, return 303 with Location: /db/questions/?query-parameters-to-retrieve-the-default-page. Then provide a different URL by which whomever is consuming your API to get statistics about the collection (e.g., what query parameters to use if s/he wants the entire collection);
While its possible to use the Range header for this purpose, I don't think that was the intent. It seems to have been designed for handling flaky connections as well as limiting the data (so the client can request part of the request if something was missing or the size was too large to process). You are hacking pagination into something that is likely used for other purposes at the communication layer.
The "proper" way to handle pagination is with the types you return. Rather than returning questions object, you should be returning a new type instead.
So if questions is like this:
<questions>
<question index=1></question>
<question index=2></question>
...
</questions>
The new type could be something like this:
<questionPage>
<startIndex>50</startIndex>
<returnedCount>10</returnedCount>
<totalCount>1203</totalCount>
<questions>
<question index=50></question>
<question index=51></question>
..
</questions>
<questionPage>
Of course you control your media types, so you can make your "pages" a format that suits your needs. If you make is something generic, you can have a single parser on the client to handle paging the same for all types. I think that is more in the spirit of the HTTP specification, rather than fudging the Range parameter for something else.