HttpClient keeps receiving bad request

Question

I'm having a hard time resolving my Bad Request responses from a REST api when I'm creating a client using C#. I tested the REST api using Fiddler 2 and executing it there, but when I'm creating the same thing programmatically I get 400 response. Here is my Fiddler composer test:

URL:

https://<third-party-rest-client>/api/v2/job 

Here are my Headers

User-Agent: Fiddler Content-Type: application/json Accept: application/json icSessionId: PomCSBCVU4VgXCJ5     Content-Length: 123 

And here is the body I'm sending a POST request with

{ "@type": "job", "taskId":"0000G20G000000000002", "taskName":"TestReplication", "taskType":"DRS", "callbackURL":"" } 

This POST comes back with a 200 response and a response body, which is perfect, but when I try to simulate the same thing in C# with this code:

public JobResponse RunJob(JobRequest jobRequest)     {         try         {             client = new HttpClient();             client.BaseAddress = new Uri(loggedUser.serverUrl + "/");             client.DefaultRequestHeaders.Clear();             client.DefaultRequestHeaders.Accept.Add(new System.Net.Http.Headers.MediaTypeWithQualityHeaderValue("application/json"));             client.DefaultRequestHeaders.TryAddWithoutValidation("icSessionId", icSessionId);              string message = JsonConvert.SerializeObject(jobRequest);             message = message.Insert(1, "\"@type\": \"job\",");             Console.WriteLine(message);             var response = client.PostAsJsonAsync("api/v2/job", message).Result;             if (response.IsSuccessStatusCode)             {                 return response.Content.ReadAsAsync<JobResponse>().Result;             }             else             {                 var result = response.Content.ReadAsStringAsync().Result;                 Console.WriteLine(result);             }         }         catch (Exception ex)         {             Console.WriteLine(ex);         }         return null;     } 

This comes back as a 400. Does anybody have any ideas what's wrong with my code?

Answer 1

Okay, I figured out the issue I was having. It seems that Serializing my JSON object into a string first, then posting it with PostAsJsonAsync was leaving all of the escape (\) characters in my object, which was why I received the Bad Request.

The problem here was my first key/value pair in my JSON object had a key with the @ symbol in it. If I try to just PostAsJsonAsync with the object, I lost the @ symbol, which gave me a Bad Request also.

What I ended up doing was Serializing the object into a string as seen above, then I converted it the a Byte Array and then created a new ByteArrayContent object passing in my byte array, adding the ContentType attribute to the ByteArrayContent Headers, then using PostAsync instead of PostAsJsonAsync. This worked perfectly.

Here is the code:

public JobResponse RunInformaticaJob(JobRequest jobRequest)     {         try         {             client = new HttpClient();             client.DefaultRequestHeaders.Clear();             client.DefaultRequestHeaders.Accept.Add(new System.Net.Http.Headers.MediaTypeWithQualityHeaderValue("application/json"));             client.DefaultRequestHeaders.TryAddWithoutValidation("Content-Type", "application/json");             client.DefaultRequestHeaders.TryAddWithoutValidation("icSessionId", icSessionId);              string message = JSONSerializer.Serialize(jobRequest);             message = message.Insert(1, "\"@type\": \"job\",");             byte[] messageBytes = System.Text.Encoding.UTF8.GetBytes(message);             var content = new ByteArrayContent(messageBytes);             content.Headers.ContentType = new System.Net.Http.Headers.MediaTypeHeaderValue("application/json");              var response = client.PostAsync(loggedUser.serverUrl + "/api/v2/job", content).Result;             if (response.IsSuccessStatusCode)             {                 return response.Content.ReadAsAsync<JobResponse>().Result;             }             else             {                 var result = response.Content.ReadAsStringAsync().Result;                 Console.WriteLine(result);             }         }         catch (Exception ex)         {             Console.WriteLine(ex);         }         return null;     } 

Issue resolved!

Answer 2

In my case examining the content of result.Content.ReadAsStringAsync().Result had the cause of the problem informing of some missing parameters and some parameters with invalid values. Corrected and it's working now.