I have code that contains several different DELETE methods, one of which takes a parameter, or at least ideally it would take a parameter. However when I make this request, either through CURL or through a web client, it doesn't work. The other DELETE requests function fine and I've hard-coded in the parameter that I want to pass just to see if the call works and it does. I've tried this with both PathParam and QueryParam and neither works. Here's how I'm using the PathParams, which I'm pretty sure is correct, QueryParams looks very similar so I don't want to post that too.
#DELETE
#Path("/byId/{id}")
public void deleteById(#PathParam("id") String id)
And then essentially the same thing for QueryParams but obviously the path is different
From what I understand a lot of RESTful APIs ignore any kind of request body with a DELETE request, or treat it as a PUT or POST. Is there any way around this? Basically I have a database that contains several objects and I need to delete one based on a unique identifier, to be passed in by the client. If there is no way around this is there some other way that I could do it?
Its possible that I'm missing something obvious here as I've only been using Jersey for a few weeks now and up to this point had never even heard of the concept of RESTful services.
You can send information to a RESTful service as either headers, path param, query param or message body.
If all the values go through as expected there is no problem with jax-rs/jersey. Now you need to debug the code and fix your implementation. jax-rs will only match a DELETE call with the DELETE http method you have implemented.
It is then your responsibility to actually perform a DELETE operation of the resource within the method. jax-rs or jersey is not going to complain if you do not DELETE or if you do some other action within the method.
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.
I would like to modify an url parameter /resource/{VaRiAbLe} in an API gateway to S3 mapping so that it actually points to /my-bucket/{variable}. That is, it accepts mixed-case input, and maps it to a lower-case name. Mapping path variables is relatively simple enough to S3 integrations, but I can't seem to get a lower-case mapping working.
Reading through the documentation for mapping parameters, it looks like the path parameters are simple string values (and not templated values), and so defining a mapping as method.request.path.variable.toLowerCase() won't work.
Does anyone have any ideas how to implement this mapping?
Map path variables to a JSON body, and then call another API method that actually does the S3 call?
Bite the bullet, and implement a Lambda function to do the S3 get for me?
Find another api method for S3 that accepts a JSON body that I can use to get the data?
Update using Orchestrated calls
Following the info from Jack, I figured I should try doing the orchestrated call, since the traffic volume is low enough that I am sure that I won't be able to keep the lambda hot.
As a proof of concept, I added two methods to my resource (sitting at /resource/{variable} - GET and POST. The GET method chains to the POST, which does the actual retrieving of the data.
POST method configuration
This is a vanilla S3 proxying method, where you set the URL Path parameter for {variable} to be method.request.body.variable.
GET method configuration
This is a HTTPS proxying method. You'll need an URL for the POST method, so you'll need to deploy the API to get the URL. The only other configuration needed here is a body mapping template with content like:
{
"variable" : "$input.params('variable').toLowerCase()",
"something" : "$input.params('something')"
}
This should be enough to get this working.
The downside to this looks to be that I'm adding an extra method (POST) to my API for that resource that could confuse consumers of the API. I think it should be possible to make the POST on the /resource resource, which would at least make a bit more sense from an API design standpoint.
Depending on how frequently this API will be called, I'd either go with the Lambda proxy or chaining two API Gateway methods together. If the API is called frequently enough to keep a Lambda function warm (say once a minute), then go with Lambda. If not, go with the orchestrated API call.
The orchestrated API call would be interesting, I'd be happy to help with that if you have questions.
As far as I know the only S3 API for getting object data is the GET that is documented in their API reference.
I have a design question on REST. I need to expose a validate method as a rest resource. Let us say it looks like this
public ValidatedResult validate(ObjectToBeValidated object)
ObjectToBeValidated is a class that contains the actual Object and also some parameters concerning the validation.
When I design this as a Restful resource, which action do I use? From my understanding GET is the action that best suits this case. If that is so, how I can pass my ObjectTobeValidated as an object but not as URL parameters? I shy away from URL parameters because ObjectToBeValidated may contain a lot of properties, ending up with an URL like below which is feel is too long
http://localhost/rest/validate?prop1=somevalu&prop2=somevalue&prop3=something&prop11=somevalu&prop22=somevalue&prop33=something
Any help would be appreciated
Thanks
Kay
The HTTP standard allows you to use the POST method. It does not necessary need to have a side effect.
The action performed by the POST method might not result in a resource
that can be identified by a URI. In this case, either 200 (OK) or 204
(No Content) is the appropriate response status, depending on whether
or not the response includes an entity that describes the result.
HTTP 1.1 / method definitions / POST
In your case you can do something like this if you want to follow the noun-verb approach Tim suggested:
POST /api/my/object/validator
Be aware that by REST the messages must be self-descriptive, so either you need a vendor MIME type or you need to add meta-data e.g. RDF to describe what this link does and what params are allowed. Otherwise we are not talking about REST, just a regular webapp.
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.
I have a Java client that calls a RESTEasy (JAX-RS) Java server. It is possible that some of my users may have a newer version of the client than the server.
That client may call a resource on the server that contains query parameters that the server does not know about. Is it possible to detect this on the server side and return an error?
I understand that if the client calls a URL that has not been implemented yet on the server, the client will get a 404 error, but what happens if the client passes in a query parameter that is not implemented (e.g.: ?sort_by=last_name)?
Is it possible to detect this on the server side and return an error?
Yes, you can do it. I think the easiest way is to use #Context UriInfo. You can obtain all query parameters by calling getQueryParameters() method. So you know if there are any unknown parameters and you can return error.
but what happens if the client passes in a query parameter that is not implemented
If you implement no special support of handling "unknown" parameters, the resource will be called and the parameter will be silently ignored.
Personally I think that it's better to ignore the unknown parameters. If you just ignore them, it may help to make the API backward compatible.
You should definitely check out the JAX-RS filters (org.apache.cxf.jaxrs.ext.RequestHandler) to intercept, validate, manipulate request, e.g. for security or validatng query parameters.
If you declared all your parameters using annotations you can parse the web.xml file for the resource class names (see possible regex below) and use the full qualified class names to access the declared annotations for methods (like javax.ws.rs.GET) and method parameters (like javax.ws.rs.QueryParam) to scan all available web service resources - this way you don't have to manually add all resource classes to your filter.
Store this information in static variables so you just have to parse this stuff the first time you hit your filter.
In your filter you can access the org.apache.cxf.message.Message for the incoming request. The query string is easy to access - if you also want to validate form parameters and multipart names, you have to reas the message content and write it back to the message (this gets a bit nasty since you have to deal with multipart boundaries etc).
To 'index' the resources I just take the HTTP method and append the path (which is then used as key to access the declared parameters.
You can use the ServletContext to read the web.xml file. For extracting the resource classes this regex might be helpful
String webxml = readInputStreamAsString(context.getResourceAsStream("WEB-INF/web.xml"));
Pattern serviceClassesPattern = Pattern.compile("<param-name>jaxrs.serviceClasses</param-name>.*?<param-value>(.*?)</param-value>", Pattern.DOTALL | Pattern.MULTILINE);