为什么发生okhttp的Post方法错误[不支持HTTP请求中指定的Content-Type头：application / x-www-form-urlencoded]？

Question

I call a Rest API of salesforce by post method:

url = "https://test-dev-ed.my.salesforce.com/services/apexrest/AccountUsers/"
    client = OkHttpClient()
     val jsonIn = FormBody.Builder()              
            .add("email",URLEncoder.encode("dt1@gmail.com", "UTF-8"))
            .add("password", URLEncoder.encode("1","UTF-8"))
            .build()
    request = Request.Builder()
            .post(jsonIn)
           .header("Authorization", "Bearer "+accesstoken)
           .addHeader("Content-Type","application/x-www-form-urlencoded")
           .url(url)
           .build()
        response = client.newCall(request).execute()

This is rest api:

@HttpPost
    global static ID createUser(String email, String password) {      
        AccountUser__c us=new AccountUser__c();
        us.Email__c=email;
        us.Password__c=password;      
        us.Status__c=0;
        insert us;      
        return us.Id;
    }  

But result return is error:

[{"errorCode":"UNSUPPORTED_MEDIA_TYPE","message":"Content-Type header specified in HTTP request is not supported: application/x-www-form-urlencoded"}]

I had try change application/json to application/x-www-form-urlencoded , but still can't resolve.

I try call a Get method, it is ok.

Why Post method occur error [Content-Type header specified in HTTP request is not supported]?

Answer 1

I would like to suggest a better resolution. Retrofit Library

Even though it is not mandatory to use Retrofit, these are few eye catchy aspects which makes it reliable and handy in similar use case of yours.

Why to use Retrofit?

• Type-safe REST Adapter that makes common networking tasks easy
• For POST operations, retrofit helps in assembling what needed to be submitted. Eg:- Generating URL encoded form.
• Takes care of URL manipulation, requesting, loading, caching, threading, synchronization, sync/async calls
• Helps to generate URL using type-aware generated code tied to specific REST API
• Parsing JSON using GSON
• Retrofit is an API adapter wrapped over OkHttp

---

The problem that you are facing can be resolved using retrofit like this.

public interface APIConfiguration{

    @Headers({"Accept:application/json",
            "Content-Type:application/x-www-form-urlencoded"})
    @FormUrlEncoded
    @POST("user/registration")
    Observable<DataPojo> registrationAPI(@FieldMap(encoded = true) Map<String, String> params);

}

That's it, with few annotation the library takes care of Form URL Encoding and related dependencies.

As it is inappropriate to start from corresponding Retrofit dependencies and sample code, you can go through Reference One and Reference Two for more details.

Answer 2

As per my understanding just checkout the difference the content type header "application/x-www-form-urlencoded" is inefficient for sending large quantities of binary data or text containing non-ASCII characters. The content type "multipart/form-data" should be used for submitting forms that contain files, non-ASCII data, and binary data. The content "multipart/form-data" follows the rules of all multipart MIME data streams.

https://www.w3.org/TR/html401/interact/forms.html#h-17.13.4

Also try your http request by setting your content type header as multipart/formdata.