B4J Question When to Use SetContentType or SetHeader("Content-Type", ...)

[mcqueccu]

Hi, Am using jOkhttputils2 to call an API

The main transaction method uses POST and the call was successful whiles using setContentType to set the header

But when using GET request to check the status of the transaction
setContentType keeps giving me an error. Meanwhile setHeader("Content-Type","application/json") works fine with the GET.

When is it right to use SetContentType and when is it right to use setHeader

Endpoint: POST
https://api.xxxxxx.com/v1/receive

Header data value
apikey xxxxxxxxxxxxxxxxxxxx
Content-Type application/json

   Dim ok As HttpJob
    ok.Initialize("",Me)
    
    ok.PostString(endpointurl,payload)    
    ok.GetRequest.SetHeader("ApiKey",apikey)    'set the header with api key
    ok.GetRequest.SetContentType("application/json")    'set the header as json
    ok.GetRequest.SetContentEncoding("UTF8")        'set encoding as utf8

Endpoint: GET
https://api.xxxxxxxx.com/v1/status/{transactionid}

Header data Value
apikey xxxxxxxxxxxxxxxxxxxx
appid xxxx
Content-Type application/json

    Dim jj As HttpJob
    jj.Initialize("",Me)
    
    jj.Download(checkUrl)   
    jj.GetRequest.SetHeader("ApiKey",apikey)   
    jj.GetRequest.SetHeader("appid",appid)
    jj.GetRequest.SetHeader("Content-Type","application/json") 'working with GET Method
'    jj.GetRequest.SetContentType("application/json")    'not working with GET method but works with POST
    jj.GetRequest.SetContentEncoding("UTF8")

Error Message whiles using SetContentType

Waiting for debugger to connect...
Program started.
Error occurred on line: 235 (HttpJob)
java.lang.RuntimeException: Request does not support this method.
    at anywheresoftware.b4h.okhttp.OkHttpClientWrapper$OkHttpRequest.SetContentType(OkHttpClientWrapper.java:493)
    at b4j.example.main$ResumableSub_AppStart.resume(main.java:138)
    at b4j.example.main._appstart(main.java:79)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at anywheresoftware.b4a.shell.Shell.runMethod(Shell.java:632)
    at anywheresoftware.b4a.shell.Shell.raiseEventImpl(Shell.java:234)
    at anywheresoftware.b4a.shell.Shell.raiseEvent(Shell.java:167)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at anywheresoftware.b4a.BA.raiseEvent2(BA.java:91)
    at anywheresoftware.b4a.shell.ShellBA.raiseEvent2(ShellBA.java:98)
    at anywheresoftware.b4a.BA.raiseEvent(BA.java:78)
    at b4j.example.main.start(main.java:38)
    at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$161(LauncherImpl.java:863)
    at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$174(PlatformImpl.java:326)
    at com.sun.javafx.application.PlatformImpl.lambda$null$172(PlatformImpl.java:295)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.application.PlatformImpl.lambda$runLater$173(PlatformImpl.java:294)
    at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.lambda$null$147(WinApplication.java:177)
    at java.lang.Thread.run(Thread.java:748)

 

[Erel]

See the documentation of SetContentType: https://www.b4x.com/android/help/okhttp.html#okhttprequest_setcontenttype

GET requests aren't expected to include the content type header. If you do need to add it to a GET request then you should use SetHeader.
You should use SetContentType for other http methods.