I have a webservice method that if I call directly via url GET returns XML without issue.
However, POST to that same url with Content-Type Json, it fails.
I think I can figure out the issue (I'm guessing it's an encoding or bad character somewhere in there) but I don't know how to debug the problem.
If I set a breakpoint in the webservice, it runs to completion. The failure appears to be happening AFTER the method returns, but BEFORE the json is returned to the caller.
How can I get in between to trace the error?
Please let me know if I can provide more context to help, but I really just need to know how to get in there.
EDIT:
The web service is configured to receive POST and return JSON and in fact DOES correctly return JSON in some cases. However, there are certain calls that are failing, so I need a way to trace this or debug it somehow and figure out why some calls are not working.
The web service is likely not configured to receive POST requests, especially if you are receiving a 405 Method Not Allowed response status.
Although I didn't find a way to debug or intercept the request to find the exact answer, it turns out the problem was the size of the content being returned by the webservice. Following this answer: ASP.NET WebMethod with jQuery json, is there a size limit?
and increasing the json limit fixed the issue!
Is there a way I could have trapped this to find the error without just guessing it was a size limit?
Related
I have a basic NIFI flow with one GenerateFlowFile processor and one LookupRecord processor with RestLookupService.
I need to do a rest lookup and enrich the incoming flow file with rest response.
I am getting errors that the lookup service is unable to lookup coordinates with the value I am extracting from the incoming flow file.
GenerateFlowFile is configured with simple JSON
LookupRecord is configured to extract the key from the JSON and populate it to the RestLookupService. Also, JsonReader and JsonSetWriter is configured to read the incoming flow file and to write the response back to the flow file
The RestLookupService itself exits with JsonParseException about unexpected character '<'
RestLookupService is configured with my API running in the cloud in which I am trying to use the extracted KEY from the incoming flow file.
The most interesting bug is that when I configure the URL to point for example to mocky.io everything works correctly so it means that the issue itself is tight with the API URL I am using (http://iotosk.ddns.net:3006/devices/${key}/getParsingData). I have tried also removing the $key, using the exact URL, using different URLs..
Of course the API is working OK over postman/curl anything else. I have checked the logs on the container that the API is running on and there is no requests in the logs what means that nifi is failing even before reaching the API. At least on application level...
I am absolutely out of options without any clue how to solve this. And with nifi also google is not helpful.
Does anybody see any issue in the configuration or can point me in some direction what can cause this issue?
After some additional digging. The issue was connected with authentication logic even
before the API receives it and that criples the request and and returned XML as Bryan Bende suggested in the comment.
But definitely better logging in nifi will help to solve this way faster...
I am writing a web service in node, and testing it with Postman. I spent a long timing looking for an error. When I finally found it, it turned out to be a simple error formatting the response body, which is json.
If I leave off the final brace in the response body, Postman waits for two minutes, and then reports that it received everything, just fine.
If I leave off the closing quote in the last value in the json, Postman says the server didn't respond, perhaps I should check my security certificates.
I would much rather Postman said "Hey, Buddy, you left off a quote!"
If there some validation service I can talk to? Or a plugin in Postman?
Here there are some validation javascript libraries, you can use:
Validator provides a declarative way of validating javascript objects.
Express-validator acts as an express.js middleware for node-validator.
Meanwhile, Postman got API testing and Collection Runner that can help you through this; which you can write some pre-request script as well as test script for each request.
Also, they got Newman which is a command-line collection runner. It allows you to effortlessly run and test a Postman collection directly from the command-line. It is built with extensibility in mind so that you can easily integrate it with your continuous integration servers and build systems.
I found that Paw worked (https://paw.cloud/). And so far I haven't paid for it.
Where Postman said "check your security certificates," Paw said "we were expecting 376 bytes but you only sent us 312."
Cuts down my time solving the problem a lot!
I use Fiddler for this. It is very good at identifying (with an error message that pops up) problems and bad implementations of the HTTP protocol. Browse the web with it running, and within a few minutes you'll undoubtedly hit a poorly implemented server.
Postman won't be able to handle these cases since it's insulated from poor behavior by the browser's framework.
That's not your problem though.
When I finally found it, it turned out to be a simple error formatting the response body, which is json.
That has absolutely nothing to do with HTTP. HTTP doesn't know or care what your request/response bodies are.
The problem you face is that your API endpoint could be returning whatever it wants. You need a custom solution to your problem, as there is no standard API server in this case.
Most folks will run unit tests that hit common endpoints of your service to ensure they're alive and well.
I should also point out that it should be all but impossible for you to break the JSON response if you're doing it correctly. Sounds like you're serializing JSON manually... never do that, we have JSON serializers for this purpose. Send in an object and let it worry about building the JSON output for you. Otherwise, you'll waste a lot of time on problems like these.
As can be seen in AngularJS's source, any $http.post request that returns an HTTP code in the 200-299 range will trigger the success() callback even if the response contains invalid data (like for example invalid JSON).
I'm specifically setting my call's responseType: 'json' and even then the success callback is fired when something else comes back. This is especially annoying in the development server where PHP's display_errors setting is turned on. When something goes wrong server-side and PHP outputs an error message the AngularJS app doesn't detect this and continues happily.
Is there a way to prevent this? I mean, to make the AngularJS app fire the error() callback when the response data is invalid JSON?
Thanks
so your PHP server responds with a 200 error code even on an error? Not knowing PHP, this feels like a server configuration problem to me. I'd expect a 500 error with a payload. That being said, there are two things that I can think of offhand.
$http includes transformResponse handlers you can set up to inspect the response for problems.
$http also includes the concept of "interceptors" which allow you to pick up the response payload and do something with it. You could use an interceptor to "reject" the response.
More information on transformResponse and "interceptors" in the $http documentation:
http://docs.angularjs.org/api/ng.$http
New here. I've searched quite a bit for a working solution to my problem, but even though I have found posts with promising titles, none of the solutions have worked.
I am deploying an MVC2 web app to a client's server.
I did my development on Win2k8 Server, but they are running Win2k3 sever.
The app's only purpose is to receive some record ID information as HTTP parameters, check in the database for the status of the given record or records, and then return the status information as a simple string such as "Completed" or "Incomplete" in JSON format.
This getJSON code works fine in the development environment.
Inexplicably to me, on the client's server, the getJSON request receives a null response from the application.
There is no cross-domain action AFAIK... the result is the same from the client's server or from my machine via VPN.
In the MVC model's Json code, a common solution for people is to add the "JsonRequestBehavior.AllowGet" attribute to the Json result being returned. I did this long before trying to deploy it, and as I said, it has worked fine in the dev environment.
Using Firebug, I have watched the same request URL get sent to both my local server and the client server - the response headers from both servers are the same, but the response content from my server is shown as:
{"Result":"No Data"}
Which is what I want.
There is literally no content shown in the response from the client's server..? But the request gets an HTTP 200 code and is recorded as a success in the reponse's status attribute.
The response header content type in both situations is "application/json"
But wait, there is more!
If I manually enter the request to each server in the Firefox nav bar, and hit enter, in both cases it responds with:
{"Result":"No Data"}
Which is what I want. So why can I get the result I want from the MVC app on the client's server only when I hand-enter the request URL in Firefox, but not from the Javascript code?
I have tried forcing different output content types ... using the jQuery ajaxSetup method...
$.ajaxSetup({
async: false,
dataType: 'text'
});
or
$.ajaxSetup({
async: false,
dataType: 'html'
});
and again wtih 'script', and 'json'. I also tried the conversion options such as 'text json' or 'html json' or 'json text' and so forth.
Some of the posts I'm reading, and my gut feeling, though, suggest the problem is not the jQuery code making the request that is at fault... I don't see how the same jQuery request point to a different server running the same app would suddenly cause that server to send back a 'null' value.
By null, I want to be clear... I mean nothing is sent. There is no {} or {null} or any sign of JSON... just blank whiteness of non-existence :P
Even if nobody knows the answer, I would love some input perhaps suggesting where I should focus my sleuthing ... client or server?
If the problem is the server, it seems hard to really know that the MVC stuff is running 100% on the IIS6 server, but in general it seems to work. I have a different MVC app running on the client server which responds to the virtual paths, and generally runs the same as on dev machine.
I have found one thing ... the request headers are somewhat different? The Request Headers sent to the IIS7 setup include an "X-Requested-With: XMLHttpRequest", "referrer" , and "cookie" field/value.
I could guess that the lack of the "X-requested-with: XMLHttpRequest" in the IIS6 request headers is a clue, but I do not see then how the same javascript code pointing at a different server can generate different request headers itself. So how else are those being generated?
The javascript is embedded in an ASP.NET page, btw.
Oooh.. frustration!
Thanks for any input.
Odd Progress ... apparently there is some sort of issue with IIS6 handling the query. Although I have not payed any attention to JSONP, a post elsewhere suggested that sometimes use the "&callback=?" parameter at the end of a .getJSON request URL would force it into GET mode and that worked frequently for problems getting data from the server. So I did that... and it did work, sort of. The proper {"Result":"No Data"} was returned in response to the request... which seems good. However, the way that the JSONP callback works, it generates its own script to do the calling and fetching and interpreting of the incoming JSON. In this case, it interprets the JSON to need a label which it does not have, thus an error is thrown "invalid label" ... there must be some way to hack things to just deliver the JSON, but the whole required use of JSONP callbacks suggests that the server configuration is wrong, right? Or why does it work without JSONP for IIS7 and not IIS6?
Despite my not liking the callback JSONP solution, it appears to work ok. The error is still returned about an invalid label, but that does not appear to stop the remaining javascript from running... and so the application is working with IIS6 now. I have not tested the fix of using the callbacks and JSONP against IIS7 yet, but I expect it will work well enough.
Here is a link to the discussion that lead me to my current solution. I do still hope to find a more elegant solution, however.
NeoWin.net
Are you certain that your App Extension Mappings are set up correct?
Follow this article for running MVC2 on IIS6 and ensure all the different configurations have been done, that's probably the first step before going further and investigating specifics.
I'm really inclined to believe it's related to HTTP Verbs.
We are in the middle of a ongoing discussion about how to handle REST exceptions.
Response Content type : JSON
Two solutions we have:
Throw all the unchecked exceptions as a JSON response.
Send Request Invalid Response code.
Arguments:
When its a error, why return JSON? Just send a invalid response code.
Counter Argument:
Response code are too technical to handle for normal developers.
Whats your say??
For a JSON API I recently developed I do both. I always respond with valid JSON (well, assuming I respond at all). If I detect an invalid request, I use status 400. If I detect a server error (which I don't believe is caused by an invalid request), I use a 5xx status. The JSON object contains a special key that is only set for errors, with a string value.
I think this is a good solution that respects REST principles, and can be used in multiple ways. The same solution is used by some other JSON APIs, such as Yahoo Search. Try http://search.yahooapis.com/ImageSearchService/V1/imageSearch?appid=YahooDemo&output=json .
Use error codes like for HTTP. So 50* for any exception cause by some internal problem. And 40* for bad arguments. Avoid using your own defined codes as far as its possible. The idea is to have a "uniform" interface.
In general.
204 for success without sending any content
200 for success with a json representation of the resource
And if its not a successful operation return appropriate response code. You can choose to optionally return a json. To simplify things you can have a common format (json) for all error responses.
http://en.wikipedia.org/wiki/REST is a must read before you freeze on your api specs.