I'm trying to connect to a companies web service, but I'm getting a BadRequest value returned. I suppose that isn't a huge issue, and I'm not asking for help on how to fix the bad request. The issue I'm running into, is how to get more details on what is causing it. So I have this HttpResponseMessage Class variable:
HttpResponseMessage response = c.Post(address, content);
//...fill in content
response = cAssessments.Post(addressInfo, content); //return "Bad Response"
I send it off to their servers with the proper content, and I get back 400 response stating "Bad Request". My question is how do I dig deeper into that repsonse variable to see exactly what is causing it. I'm figuring that there is some dependance on the service I'm hitting to supply information so I'm going to assume it's in there somewhere. But what are something things inside that variable I should be looking into? For example:
"response.StatusCode" gives me the the 400 code. What other properties can I look into?
Any help is appreciated.
Filling content of BadRequest response with some useful tip or information what could possibly go wrong is totally up to web service which serves response. You cant do anything from your side.
Try the Content itself, also the URL of the originating request.
Depending on the API you're requesting against, they may include what specifically caused the 400 in the response's Content.
Also the format you are requesting it in (json vs xml vs whatever)
It all depends on what the service is returning. To check that, you can read the response stream:
using (var stream = response.GetResponseStream ()){
using (var reader = new StreamReader(stream, Encoding.UTF8)
{
var text = reader.ReadToEnd();
// text contains your info
}
}
Another useful option for debugging is using something like postman, where you can paste in your request and see the full response immediately
If the response doesn't include any useful info, you're stuck though, there's nothing you can do about that.
Related
I really am not sure what is happening.
I'm using an HttpClient to post XML content to a remote server using the PostAsync method like this:
using var content = new StringContent(payload, Encoding.UTF8, "application/xml");
using var response = await _httpClient.PostAsync(string.Empty, content);
... where payload is a string, and relative uri is empty because I just need to call base uri of httpclient.
I can perform same request in Postman and it works fine.
The issue is, for some reason httpclient actually performs a GET request instead of POST, and ignores content whatsoever:
I've checked in Postman, and it seems like it is a normal response from the server to GET request.
I've also tried
using var response = await _httpClient.SendAsync(new HttpRequestMessage(HttpMethod.Post, string.Empty){Content = content});
... and it gives the same result.
This looks like a very weird issue to me, as I've never seen http client behaving like this in the past. Could anyone please explain why is this happening? Thanks!
OK, so the issue was actually with server.
It redirected all the requests with URLs not ending with "/", like http://address.com/page to the same address but ending with "/" - http://address.com/page/, and lost the method and content in process.
As #Jimi mentioned, the RequestMessage field in HttpResponseMessage contains the info about the last request that reached the server, therefore initial request data was lost, and I mistook it for HttpClient making wrong requests.
I get this error when using the CustomVisionPredictionClient like so:
var predictionApi = new CustomVisionPredictionClient()
{
ApiKey = _predictionKey,
Endpoint = "https://westeurope.api.cognitive.microsoft.com"
};
var result = await predictionApi.ClassifyImageAsync(project.Id, _modelName, imageData);
The project/project id is retrieved via the training API, on which I can call GetProjects() without a problem. It should be correct, if I change it to something wrong I get a "not found" exception.
_modelName is the published name of the iteration ("xxxRecognition", see screenshot below), it should also be correct, when I change it I get "not found".
imageData is just a FileStream from a PNG image.
The problem was that I created an "Object Detection" type project and tried to use it with ClassifyImage() which has to be used with "Classification" type projects. So I have to use DetectImage() instead. :)
There's two items to address here.
Your particular "Bad Request"
Your example, specifically, has one or more of these problems that you haven't really included.
The _modelName is malformed
The imageData is not formatted properly
Some configuration, likely of request headers, is missing or incorrect
That's about the most we can provide from the example you've given. But here's the other concern that will benefit you greatly in the future: "Bad Request" tells you a lot about what's happened.
More about "Bad Request" in general
If you look at ranges within HTTP status codes you'll notice a pattern in the "error" ranges.
In 4xx the requester (you) did something wrong and you can correct it.
In 5xx the responder did something wrong and you cannot correct it.
Beneath that:
In 404 Not Found it seems the request was formed well but the responder cannot find what you've asked for
In 401 Unauthorized you didn't provide any kind of identity
In 403 Forbidden you did provide an identity but you're not allowed to perform this action
But in 400 Bad Request the responder couldn't validate your request as good input at all. That means you can look at the API documentation again, compare it with your implementation, and try again.
I want to call an endpoint with a Put command.
In Postman
I can put example https://example.com/customers/106. I then add a body of type application/json (under raw).
When I Put this body to the endpoint, I get a 200 OK.
The endpoint I use requires two custom headers and a content-type, which I have made under headers. So I add three headers: X-AppSecretToken, X-AgreementGrantToken and the Content-Type (to application/json).
In RestSharp
Here I use the following. The putstr is the exact same body I Put as I do in Postman:
var restclient = new RestSharp.RestClient("https://example.com");
var request = new RestRequest("/customers/" + customerId, Method.PUT);
request.AddHeader("X-AppSecretToken", systemToken);
request.AddHeader("X-AgreementGrantToken", userToken);
request.AddHeader("Accept", "application/json");
request.AddJsonBody(putstr);
var response = restclient.Execute(request);
Now, when I do this, I get the following response which is a custom error from the API I am calling:
"{\"message\":\"Error converting value SOME STUFF}}\\\" to type 'eco.rest.Models.Customer'. Path '', line 1, position 605.\",\"errorCode\":\"E00500\",\"developerHint\":\"The JSON payload could not be parsed. The error message should give you a good indication of where the error is located. One common reason for this error is a missing '{' or a '}' in your payload.\",\"logId\":\"123fc6fb4964a141f612ae8ae7571446\",\"httpStatusCode\":400,\"logTime\":\"2018-05-20T21:56:56\"}"
How to fix?
Normally, I'd never ask this question. If someone else asked, I would say: open Fiddler or a similar tool and see how requests are different.
I have some troubles with this, because it's HTTPS.
When I debug through my code, I simply don't see the call inside Fiddler. I also installed Charles, but also no luck. Not sure what the problem is.
However, I thought that someone who reads this can probably come up with the problem. My own assumptions are I maybe have added the headers in a wrong way, the JSON body is encoded different or similar - but I am really unsure how to move on. I hope someone can help!
Your putstr value seems to be a JSON value.
AddJsonBody will convert this JSON value into another JSON value.
You should use the original object instead of putstr.
It seems to be occurring only one machine and none of the other machines.
HttpWebRequest myRequest =(HttpWebRequest)WebRequest.Create("https://connect.zystemsgo.com/auto/");
myRequest.Method = "GET";
SetCertificatePolicy();
Application.DoEvents();
WebResponse myResponse = myRequest.GetResponse();
StreamReader sr = new StreamReader(myResponse.GetResponseStream(),System.Text.Encoding.UTF8);
string result = sr.ReadToEnd();
I tried searching other 400 request errors, but it is not clear. How do I go about debugging this?
HTTP Error 400 means Bad Request. This is being returned by the server.
Usually, when I'm debugging HTTP requests, I use Fiddler to monitor the requests and responses and find out what's going on. It never fails.
(Not really an answer, but too big for comment)
For what it's worth, I ran the following Python code (too lazy to spin up C# :), and it worked fine:
import httplib
conn = httplib.HTTPSConnection('connect.zystemsgo.com')
conn.request('GET', '/auto/')
resp = conn.getresponse()
data = resp.read()
print data # expected ouput, just like visiting in a browser
print resp.status # 200
Are you sure you are showing us the URL that is actually failing, or is your code a more general example?
Perhaps the server certificate is not installed on that machine? I wouldn't expect a HTTP 400 in that case, but it's the only thing I can think of so far...
it is a bad request error .Are there no parameters in the request?
Can you post the response message,it will give some idea of what is going wrong.
The code that i supplied in the comment above works.
WebClient webClient = new WebClient();
webClient.DownloadFile("Your complete url for the file", #"c:\myfile.txt");
you need to have permission to write in the directory of your choice.
You could also try and use the async download if you want.I am not getting why it would not work on a certain machine.
I have a C# console app (.NET 2.0 framework) that does an HTTP post using the following code:
StringBuilder postData = new StringBuilder(100);
postData.Append("post.php?");
postData.Append("Key1=");
postData.Append(val1);
postData.Append("&Key2=");
postData.Append(val2);
byte[] dataArray = Encoding.UTF8.GetBytes(postData.ToString());
HttpWebRequest httpRequest = (HttpWebRequest)WebRequest.Create("http://example.com/");
httpRequest.Method = "POST";
httpRequest.ContentType = "application/x-www-form-urlencoded";
httpRequest.ContentLength = dataArray.Length;
Stream requestStream = httpRequest.GetRequestStream();
requestStream.Write(dataArray, 0, dataArray.Length);
requestStream.Flush();
requestStream.Close();
HttpWebResponse webResponse = (HttpWebResponse)httpRequest.GetResponse();
if (httpRequest.HaveResponse == true) {
Stream responseStream = webResponse.GetResponseStream();
StreamReader responseReader = new System.IO.StreamReader(responseStream, Encoding.UTF8);
String responseString = responseReader.ReadToEnd();
}
The outputs from this are:
webResponse.ContentLength = -1
webResponse.ContentType = text/html
webResponse.ContentEncoding is blank
The responseString is HTML with a title and body.
However, if I post the same URL into a browser (http://example.com/post.php?Key1=some_value&Key2=some_other_value), I get a small XML snippet like:
<?xml version="1.0" ?>
<RESPONSE RESULT="SUCCESS"/>
with none of the same HTML as in the application. Why are the responses so different? I need to parse the returned result which I am not getting in the HTML. Do I have to change how I do the post in the application? I don't have control over the server side code that accepts the post.
If you are indeed supposed to use the POST HTTP method, you have a couple things wrong. First, this line:
postData.Append("post.php?");
is incorrect. You want to post to post.php, you don't want post the value "post.php?" to the page. Just remove this line entirely.
This piece:
... WebRequest.Create("http://example.com/");
needs post.php added to it, so...
... WebRequest.Create("http://example.com/post.php");
Again this is assuming you are actually supposed to be POSTing to the specified page instead of GETing. If you are supposed to be using GET, then the other answers already supplied apply.
You'll want to get an HTTP sniffer tool like Fiddler and compare the headers that are being sent from your app to the ones being sent by the browser. There will be something different that is causing the server to return a different response. When you tweak your app to send the same thing browser is sending you should get the same response. (It could be user-agent, cookies, anything, but something is surely different.)
I've seen this in the past.
When you run from a browser, the "User-Agent" in the header is "Mozilla ...".
When you run from a program, it's different and generally specific to the language used.
I think you need to use a GET request, instead of POST. If the url you're using has querystring values (like ?Key1=some_value&Key2=some_other_value) then it's expecting a GET. Instead of adding post values to your webrequest, just put this data in the querystring.
HttpWebRequest httpRequest = (HttpWebRequest)WebRequest.Create("http://example.com/?val1=" + val1 + "&val2=" + val2);
httpRequest.Method = "GET";
httpRequest.ContentType = "application/x-www-form-urlencoded";
....
So, the result you're getting is different when you POST the data from your app because the server-side code has a different output when it can't read the data it's expecting in the querystring.
In your code you a specify the POST method which sends the data to the PHP file without putting the data in the web address. When you put the information in the address bar, that is not the POST method, that is the GET method. The name may be confusing, but GET just means that the data is being sent to the PHP file through the web address, instead of behind the scenes, not that it is supposed to get any information. When you put the address in the browser it is using a GET.
Create a simple html form and specify POST as the method and your url as the action. You will see that the information is sent without appearing in the address bar.
Then do the same thing but specify GET. You will see the information you sent in the address bar.
I believe the problem has something to do with the way your headers are set up for the WebRequest.
I have seen strange cases where attempting to simulate a browser by changing headers in the request makes a difference to the server.
The short answer is that your console application is not a web browser and the web server of example.com is expecting to interact with a browser.
You might also consider changing the ContentType to be "multipart/form-data".
What I find odd is that you are essentially posting nothing. The work is being done by the query string. Therefore, you probably should be using a GET instead of a POST.
Is the form expecting a cookie? That is another possible reason why it works in the browser and not from the console app.