Getting Bad Request error while updating email category with Office 365 API and HttpClient in C#

Question

I'm trying to to update email category and also mark it as read after that with the help of Outlook 365 API and HttpClient. Following this tutorial.

In the tutorial the code is as below to update category and mark as read but, I'm not getting that how should I attach these details to HttpClient and request.

PATCH https://outlook.office.com/api/v2.0/me/messages/AAMkAGE0Mz8S-AAA=
Content-Type: application/json

{
"Categories": [
"Orange category",
"Green category"
],
"IsRead": true
}

The method and HttpClient I'm using are as below:

Update 1

public string UpdateCategory(AuthenticationResult result, string mediator)
    {
    //HTTPMethod.PATCH not available to adding it manualy.
    var httpMethod = new HttpMethod("PATCH");
    HttpRequestMessage request = new HttpRequestMessage(httpMethod, mediator);
    request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", result.AccessToken);
    //JSON in a string variable for test
    var tempJson = @"{""Categories"" : ""Checking""}";
    Converting string to JSON
    var jsonData = JsonConvert.SerializeObject(tempJson);
    //Adding the JSON to request.Content
    request.Content =new StringContent(jsonData,Encoding.UTF8, "application/json");
    HttpResponseMessage response = httpClient.SendAsync(request).Result;
    if (!response.IsSuccessStatusCode)
     throw new WebException(response.StatusCode.ToString() + ": " + response.ReasonPhrase);
    mediator = response.Content.ReadAsStringAsync().Result;
    return mediator;
    }

It's throwing Bad Request error.

I am using 365 API with a WPF application. Please advise.

Answer 1

Finally got solution. Here it is for newbies like me.

What was the error -

When I request API with PATCH with body I was getting Bad Request error.

What I was doing wrong -

When I evaluated my request with this awesome tool for testing outlook 365 API, I come to know the error which was

"error": {
    "code": "RequestBodyRead",
    "message": "An unexpected 'PrimitiveValue' node was found when reading from the JSON reader. A 'StartArray' node was expected."
}

This error meant I was sending wrong data. I was sending string to a List<string>. This is really silly I know but it happens right? ;)

So, to correct this instead of passing JSON as fixed string, I created a class with a List<string> property as below to have flexibility to input category as want.

public class ChangeEmailCategory
{
    public List<string> Categories { get; set; }

}

And here is final method.

//Passing parameters - AuthenticationResult, URI with authentication header, List of categories.
public string UpdateCategory(AuthenticationResult result, string uriString,List<string> categories)
    {
        //HTTPMethod.PATCH not available so adding it manualy.
        var httpMethod = new HttpMethod("PATCH");
        HttpRequestMessage request = new HttpRequestMessage(httpMethod, uriString);
        request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", result.AccessToken);
        ChangeEmailCategory cec = new ChangeEmailCategory();
        cec.Categories = categories;
        //Serializing class properties as JSON
        var jsonData = JsonConvert.SerializeObject(cec);
        //Adding JSON to request body
        request.Content =new StringContent(jsonData,Encoding.UTF8, "application/json");
        HttpResponseMessage response = httpClient.SendAsync(request).Result;
        if (!response.IsSuccessStatusCode)
            throw new WebException(response.StatusCode.ToString() + ": " + response.ReasonPhrase);
        return response.Content.ReadAsStringAsync().Result;
    }

Here is method call.

List<string> categories = new List<string>();
categories.Add("Checking");
//utility is my class containing method
utility.UpdateCategory(result, categoryChangeUri, categories);

That's all! It took me one day to learn and figure it out. Thanks to all posts on Stack Overflow and google which I referred but not remember not to mention here.

If anyone need any additional information regarding this do let me know. Just mention me in comments. I will try to help.