I'm building a CalDAV server (in Java, using third-party library), pls help me with this:
If the request is: return all events in a calendar whose start date is between [date1, date2], then what type of request is it? and the parameters of the request?
I intend to put a servlet for a client to query. I'm wondering if I have to make a servlet for each type of requests: GET,HEAD,OPTIONS,PUT (target exists),PUT (no target exists),PROPPATCH,PROPFIND,DELETE,LOCK (target exists),LOCK (no target exists), MKCOL, MKCALENDAR,UNLOCK,REPORT,FREEBUSY
Thanks.
First question: You want to use a timerange based calendar query. See https://www.rfc-editor.org/rfc/rfc4791#section-7.8.1
Second question: You need only one servlet. Typically, you verwrite its default service() method to dispatch to separate handlers, one for each method (REPORT, PUT,...).
Related
I commence in REST and I have some questions:
What type must the controller return? Typically, I'm asking if my Rest #Controller must return Item object as it is or encapsulate it in ResponseEntity in order to specify http-status-code.
What http status code to use in a GET method on a particular item ("/items/2") if the given item does not exists: HttpMediaStatus.OK(200) and null return or HttpStatus.NO_CONTENT(204) and null return ?
Second part: I saw it was possible to specify #Produces and #Consumes on WS method but what the use of that? My application and my methods work so, why specify MediaType.APPLICATION_JSON_VALUE? Doesn't Spring/SpringBoot automatically convert Item or ResponseEntity into json?
Context: using Spring Boot, hibernate, REST webservice.
Thank you.
Many questions in one, I'll provide short answers with a bunch of link to relevant articles and the reference documentation.
What type must the controller return?
Depends on your annotation and the RESTful-ness of your service. There are three annotations you can use for controllers: #Controller, #RestController and #RepositoryRestController.
Controller is the base annotation to mark your class as a controller. The return type of the controller endpoint methods can be many things, I invite you to read this dedicated post to get a grasp of it.
When developing a pure-REST service, you will focus on using RestController and RepositoryRestController.
RestControlleris Controller + ResponseBody. It binds the return value of the endpoint method to the web response body:
#RestController
public ItemController {
#RequestMapping("/items/{id}")
public Item getItem(#PathVariable("id") String id) {
Item item = ...
return item;
}
}
With this, when you hit http:/.../api/items/foo, Spring does its magic, automatically converting the item to a ResponseEntity with a relevant 40X status code and some default HTTP headers.
At some point, you will need more control over the status code and headers, while still benefiting from Spring Data REST's settings. That's when you will use RepositoryRestController with a ResponseEntity<Item> as return type, see the example the Spring Data REST reference.
What http status code to use in a GET method on a particular item if the given item does not exists?
Bluntly said: use HttpStatus.NOT_FOUND. You're looking for a resource that does not exist, there's something wrong.
That being said, it is completely up to you to decide how to handle missing resources in your project. If your workflow justifies it, a missing resource could be something completely acceptable that indeed returns a 20X response, though you may expect users of your API to get confused if you haven't warned them or provided some documentation (we are creatures of habits and conventions). But I'd still start with a 404 status code.
(...) #Produces and #Consumes on WS method but what the use of that? My application and my methods work so, why specify MediaType.APPLICATION_JSON_VALUE? Doesn't Spring/SpringBoot automatically convert Item or ResponseEntity into json?
#Consumes and #Produces are respectively matched against content-type and accept headers from the request. It's a mean of restricting the input accepted and the output provided by your endpoint method.
Since we're talking about a REST service, communications between clients of the API and the service are expected to be JSON-formatted. Thanks to Spring HATEOAS, the answer are actually formatted with the application/hal+json content-type.
In that scenario, you can indeed not bother with those two annotations. You will need them if you develop a service that accepts different content-types (application/text, application/json, application/xml...) and provides, for instance, HTML views to users of your website and JSON or XML response to automated clients of your service.
For real life examples:
Facebook provides the Graph API for applications to read to/write from its graph, while users happily (?) surf on web pages
Google does the same with the Google Maps API
I'm developing a scala application with play frame work, i have created a filter that filters every request coming from outside server,but now i'm stuck on how can i run a filter on demand since two days,i have 80 APIs 30 of them needs to run a specific filter, how can i read the request route template while the requests like this
GET /api/v1/:locale/:uuid core.controllers.MyClass.myAction1(locale: String)
GET /api/v1/:locale/:uuid/MyRoute core.controllers.MyClass.myAction2(locale: String)
GET /api/v1/:locale/:uuid/Foo core.controllers.MyClass.myAction3(locale: String)
GET /api/v1/:locale/orders/:orderId core.controllers.MyClass.myAction4(locale: String)
well, those routes are placed in routes file,
in filter i need to check weather if the route has :uuid variable or :orderId in order to run its specific filter, because both of their ids, i getting them as uuid so i couldn't expect the request, could i read the route template ?
You can access to some routing information from the RequestHeader#attrs:
// in your filter
val handlerDef: Option[HandlerDef] = request.attrs.get(Router.Attrs.HandlerDef)
See HandlerDef api
If you want to choose 30 out of 80 actions to run some common logic, you could also consider using "action builders" to provide that logic.
When you use Action { ... } you get a vanilla action. You can also make your own MyAction { ... } that wraps a normal Action and runs custom logic. This is an ActionBuilder. If you use this approach you just need to update your 30 actions to use that custom action builder.
See: https://www.playframework.com/documentation/2.6.x/ScalaActionsComposition#Custom-action-builders
Our API's entry point has a rel named "x:reports" (where x is a prefix defined in the HAL representation, by way of a curie - but that's not important right now).
There are several types of reports. Following "x:report" provides a set of these affordances, each with a rel of its own - one rel is named "x:proofofplay". There is a set of lookup values associated with this type of report (and only this type of report). The representation returned by following "x:proofofplay" has a rel to this set of values "x:artwork".
This results in the following hierarchy
reports
proofofplay
artwork
While the "x:artwork" resource is fairly small, it does take some time to fetch it (10 sec). So the client has opted to async load it at app launch.
In order to get the "x:artwork"'s href the client has to follow the links. I'm not sure whether this is a problem. It seems potentially unRESTful, as the client is depending on out-of-band knowledge of the path to this resource. If ever path to artwork changes (highly unlikely) the client will break (though the hrefs themselves can change with impunity).
To see why I'm concerned, the launch function looks like this:
launch: function () {
var me = this;
Rest.getLinksFromEntryPoint(function(links) {
Rest.getLinksFromHref(links["x:reports"].href, function(reportLinks){
Rest.getLinksFromHref(reportLinks["x:proofofplay"].href, function(popLinks){
me.loadArtworks(popLinks["x:artwork"].href);
});
});
});
}
This hard-coding of the path simultaneously makes me think "that's fine - it's based on a published resource model" and "I bet Roy Fielding will be mad at me".
Is this fine, or is there a better way for a client to safely navigate such a hierarchy?
The HAL answer to this is to embed the resources.
Depending a bit on your server-side technology, this should be good enough in your case because you need all the data to be there before the start of the application, and since you worry about doing this sequentially, you might parallelize this on the server.
Your HAL client should ideally treat things in _links and things in _embedded as the same type of thing, with the exception that in the second case, you are also per-populating the HTTP cache for the resources.
Our js-based client does something like this:
var client = new Client(bookMarkUrl);
var resource = await client
.follow('x:reports')
.follow('x:proofofplay')
.follow('x:artwork')
.get();
If any of these intermediate links are specified in _links, we'll follow the links and do GET requests on demand, but if any appeared in _embedded, the request is skipped and the local cache is used. This has the benefit that in the future we can add new things from _links to _embedded, and speeding up clients who don't have to be aware of this change. It's all seamless.
In the future we intend to switch from HAL's _embedded to use HTTP2 Push instead.
I'm currently working on ng-admin.
I'm having a problem retrieving user data from my REST API (connected to a MongoDB) and displaying it.
I have identified the problem as the following:
When I enter http://localhost:3000/users into my browser, I get a list of all users in my database.
When I enter http://localhost:3000/users?_page=1&_perPage=30&_sortDir=DESC&_sortField=id,
I get [] as a result.
I am quite new to this, I used both my browser and the POSTMAN Chrome extension to test this and get the same result.
http://localhost:3000/users_end=30&_order=DESC&_sort=id&_start=0
This (/users_end) is a different request than /users.
It should be:
http://localhost:3000/users?end=30&_order=DESC&_sort=id&_start=0
Or, by looking at the other parameters:
http://localhost:3000/users?_end=30&_order=DESC&_sort=id&_start=0
with end or _end being the first parameter (mark the ?).
Update (it is ? and before the _, I have edited.):
If adding parameters to the request returns an empty list, try adding only one at a time to narrow down the problem (there's probably an error in the usage of those parameters - are you sure you need those underscores?).
Your REST API must have a way to handle pagination, sorting, and filtering. But ng-admin cannot determine exactly how, because REST is a style and not a standard. So ng-admin makes assumptions about how your API does that by default, that's why it adds these _end and _sort query parameters.
In order to transform these parameters into those that your API understands, you'll have to add an interceptor. This is all thoroughly explained in the ng-admin documentation: http://ng-admin-book.marmelab.com/doc/API-mapping.html
I'm running into a problem with adding a query to the callback URL. I'm getting an invalid URI scheme error attempting to authorize the following string:
https://www.linkedin.com/uas/oauth2/authorization?response_type=code&client_id=75df1ocpxohk88&scope=rw_groups%20w_messages%20r_basicprofile%20r_contactinfo%20r_network&state=7a6c697d357e4921aeb1ba3793d7af5a&redirect_uri=http://marktest.clubexpress.com/basic_modules/club_admin/website/auth_callback.aspx?type=linkedin
I've read some conflicting information in forum posts here. Some say that it's possible to add query strings to callbacks, and others say that it results in error.
If I remove ?type=linkedin, I can authorize just fine and receive the token. It would make my life so much easier if I could use a query string on the callback url, as I need to do some additional processing in the callback.
In short, can I append a query string to the end of the callback url?
For fun, I tried encoding the callback url in the request (obviously this is a no-no according to their documentation):
https://www.linkedin.com/uas/oauth2/authorization?response_type=code&client_id=75df1ocpxohk88&scope=rw_groups%20w_messages%20r_basicprofile%20r_contactinfo%20r_network&state=5cabef71d89149d48df523558bd12121&redirect_uri=http%3a%2f%2fmarktest.clubexpress.com%2fbasic_modules%2fclub_admin%2fwebsite%2fauth_callback.aspx%3ftype%3dlinkedin
This also resulted in an error but was worth a shot.
The documetation here: https://developer.linkedin.com/forum/oauth-20-redirect-url-faq-invalid-redirecturi-error indicates that you CAN use query parameters. And in the first request, it appears that I'm doing it correctly. Post #25 on this page - https://developer.linkedin.com/forum/error-while-getting-access-token indicates that you have to remove the query parameters to make it work
Anyone have experience with successfully passing additional query paramaters in the callback url for the linkedin API using oAuth2.0? If so, what am I doing wrong?
I couldn't wait around for the Linkedin rep's to respond. After much experimentation, I can only surmise that the use of additional query parameters in the callback is not allowed (thanks for making my application more complicated). As it's been suggested in post #25 from the question, I've tucked away the things I need in the "state=" parameter of the request so that it's returned to my callback.
In my situation, I'm processing multiple API's from my callback and requests from multiple users, so I need to know the type and user number. As a solution, I'm attaching a random string to a prefix, so that I can extract the query parameter in my callback and process it. Each state= will therefore be unique as well as giving me a unique key to cache/get object from cache..
so state="Linkedin-5hnx5322d3-543"
so, on my callback page (for you c# folks)
_stateString=Request["state"];
_receivedUserId = _stateString.Split('-')[2];
_receivedCacheKeyPrefix = _stateString.Split('-')[0];
if(_receivedCacheKeyPrefix == "Linkedin") {
getUserDomain(_receivedUserId);
oLinkedIn.AccessTOkenGet(Request["code"],_userDomain);
if (oLinkedin.Token.Length > 0) {
_linkedinToken = oLinkedin.Token;
//now cache token using the entire _statestring and user id (removed for brevity)
}
You not allowed to do that.
Refer to the doc: https://developer.linkedin.com/docs/oauth2
Please note that:
We strongly recommend using HTTPS whenever possible
URLs must be absolute (e.g. "https://example.com/auth/callback", not "/auth/callback")
URL arguments are ignored (i.e. https://example.com/?id=1 is the same as https://example.com/)
URLs cannot include #'s (i.e. "https://example.com/auth/callback#linkedin" is invalid)