Sending http requests in C# with Unity

Question

How can I send HTTP GET and POST requests in C# with Unity?

What I want is:

send json data in post request (I use Unity serializer, so no need in new one, I just want to pass a string in post data and have the ability to set ContentType to application/json);
get response code and body without any problems;
do it all asynchronously without blocking UI rendering.

What I've tried:

implementing with HttpWebRequest/HttpWebResponse, but it's too hard and low level (if I won't find anything better, I'll have to use it);
using Unity WWW, but it doesn't match my requirements;
using some external packages from NuGet - Unity doesn't accept them :(

Most problems were with threading, I'm not experienced enough in it in C#. IDE, I use, is Intellij Rider.

If you want to do this async, you should use WWW and IEnumerator that Unity provides, if it's not what you wanted, then write own HttpClient with threading, but it's complicated — Markiian Benovskyi
– Markiian Benovskyi, Commented Sep 1, 2017 at 16:04
You can use NuGet packages with Unity, see this Open Source plugin to use promises instead of Coroutines github.com/proyecto26/RestClient — jdnichollsc
– jdnichollsc, Commented Jan 12, 2019 at 9:04

Nick is tired · Accepted Answer · 2021-12-31 16:32:16Z

The WWW API should get this done but UnityWebRequest replaced it so I will answer the newer API. It's really simple. You have to use coroutine to do this with Unity's API otherwise you have have to use one of C# standard web request API and Thread. With coroutine you can yield the request until it is done. This will not block the main Thread or prevent other scripts from running.

Note:

^{For the examples below, if you are using anything below Unity 2017.2, replace SendWebRequest() with Send() and then replace isNetworkError with isError. This will then work for the lower version of Unity. Also, if you need to access the downloaded data in a binary form instead, replace uwr.downloadHandler.text with uwr.downloadHandler.data. Finally, the SetRequestHeader function is used to set the header of the request.}

GET request:

void Start() { StartCoroutine(getRequest("http:///www.yoururl.com")); } IEnumerator getRequest(string uri) { UnityWebRequest uwr = UnityWebRequest.Get(uri); yield return uwr.SendWebRequest(); if (uwr.isNetworkError) { Debug.Log("Error While Sending: " + uwr.error); } else { Debug.Log("Received: " + uwr.downloadHandler.text); } }

POST request with Form:

void Start() { StartCoroutine(postRequest("http:///www.yoururl.com")); } IEnumerator postRequest(string url) { WWWForm form = new WWWForm(); form.AddField("myField", "myData"); form.AddField("Game Name", "Mario Kart"); UnityWebRequest uwr = UnityWebRequest.Post(url, form); yield return uwr.SendWebRequest(); if (uwr.isNetworkError) { Debug.Log("Error While Sending: " + uwr.error); } else { Debug.Log("Received: " + uwr.downloadHandler.text); } }

POST request with Json:

 void Start() { StartCoroutine(postRequest("http:///www.yoururl.com", "your json")); } IEnumerator postRequest(string url, string json) { var uwr = new UnityWebRequest(url, "POST"); byte[] jsonToSend = new System.Text.UTF8Encoding().GetBytes(json); uwr.uploadHandler = (UploadHandler)new UploadHandlerRaw(jsonToSend); uwr.downloadHandler = (DownloadHandler)new DownloadHandlerBuffer(); uwr.SetRequestHeader("Content-Type", "application/json"); //Send the request then wait here until it returns yield return uwr.SendWebRequest(); if (uwr.isNetworkError) { Debug.Log("Error While Sending: " + uwr.error); } else { Debug.Log("Received: " + uwr.downloadHandler.text); } }

POST request with Multipart FormData/Multipart Form File:

void Start() { StartCoroutine(postRequest("http:///www.yoururl.com")); } IEnumerator postRequest(string url) { List<IMultipartFormSection> formData = new List<IMultipartFormSection>(); formData.Add(new MultipartFormDataSection("field1=foo&field2=bar")); formData.Add(new MultipartFormFileSection("my file data", "myfile.txt")); UnityWebRequest uwr = UnityWebRequest.Post(url, formData); yield return uwr.SendWebRequest(); if (uwr.isNetworkError) { Debug.Log("Error While Sending: " + uwr.error); } else { Debug.Log("Received: " + uwr.downloadHandler.text); } }

PUT request:

void Start() { StartCoroutine(putRequest("http:///www.yoururl.com")); } IEnumerator putRequest(string url) { byte[] dataToPut = System.Text.Encoding.UTF8.GetBytes("Hello, This is a test"); UnityWebRequest uwr = UnityWebRequest.Put(url, dataToPut); yield return uwr.SendWebRequest(); if (uwr.isNetworkError) { Debug.Log("Error While Sending: " + uwr.error); } else { Debug.Log("Received: " + uwr.downloadHandler.text); } }

DELETE request:

void Start() { StartCoroutine(deleteRequest("http:///www.yoururl.com")); } IEnumerator deleteRequest(string url) { UnityWebRequest uwr = UnityWebRequest.Delete(url); yield return uwr.SendWebRequest(); if (uwr.isNetworkError) { Debug.Log("Error While Sending: " + uwr.error); } else { Debug.Log("Deleted"); } }

Like I said, UnityWebRequest is implemented to run in another Thread. coroutine is used to wait/yield for it to finish the request. The yield is imply waiting for UnityWebRequest which is one another Thread to finish. It does not block the main Thread while yielding. That's why coroutines are awesome.
My examples shows how to make a http request and also with json. If you copy the json example as it is and paste in your Editor without modifying it, it should work. If you modify it and it doesn't work, create a new question. Before you create a new question, I want to tell you the problem I found in your code. execute is a coroutine function and should not be called directly like you did. It should be called with StartCoroutine(execute()) function. Take a look at my example again. You must add the yield return uwr.SendWebRequest(); otherwise you will have issues in the future.
Finally, the class with the coroutine(execute) function must inherit from MonoBehaviour before you can use StartCoroutine function to start the coroutine function. Your class does not inherit from MonoBehaviour. If you don't want to inherit from MonoBehaviour, see my answer here as I described how to do this without inheriting from MonoBehaviour. Please fix all these before replying to this comment. If you run into a problem, ask a new question but post your code in that question.
@Bluetree Yes, it should work on any platform Unity supports.
@Bluetree It's right there in my answer. See the MultipartFormFileSection under that second. See many of its constructor overload here.

Jonathan · Accepted Answer · 2017-09-01 15:57:54Z

Use HttpClient and something like:

public static HttpContent DoPost(object payload, string subPath) { var httpClient = new HttpClient(); HttpClient.BaseAddress = new Uri(Global.BaseUrl); HttpClient.DefaultRequestHeaders.Clear(); HttpClient.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json")); // if you're using json service // make request var response = Global.HttpClient.PostAsJsonAsync(subPath.TrimLeadingSlash(), payload).Result; // check for error response.EnsureSuccessStatusCode(); // return result return response.Content; }

Payload is an object to be serialized to json. If all requests are going to the same baseUrl, you can set up HttpClient globally, and reuse it here

Looks clear. I'll try it. But what about doing it asynchronous?
.Result on the end of the request is what makes it synchronous. If you remove that, you can use task / await, etc
there is no HttpClient class found... And package System.Net.Http doesn't exist.
yes... you can't use HttClient class from Unity in this moment with the current version of the .NET Framework (3.5)
Unity supports 4.5 if you change the settings in the engine. for unity versions 2017.x and up.

Omdevsinh Gohil · Accepted Answer · 2021-06-02 13:07:18Z

https://www.patrykgalach.com/2019/04/18/how-to-call-rest-api-in-unity/

Please refer this link cleanest way to play with data

and do not use www instead of use UnityWebRequest

Codemaker2015 · Accepted Answer · 2022-09-06 16:35:39Z

We can use WWW and UnityWebRequest classes to initiate API calls. WWW got obsolete now and Unity recommends using UnityWebRequest over WWW.

void Start() { string url = "https://retrofit-backend-demo.herokuapp.com/book"; StartCoroutine(GetBooksUsingWWW(url)); StartCoroutine(GetBooksUsingUnityWebRequest(url)); } IEnumerator GetBooksUsingWWW(string url) { using (WWW www = new WWW(url)){ yield return www; Debug.Log(www.text); JSONNode jsonNode = JSON.Parse(www.text); string title = jsonNode[0]["title"].ToString(); Debug.Log("Title: " + title); } } IEnumerator GetBooksUsingUnityWebRequest(string url) { UnityWebRequest www = UnityWebRequest.Get(url); yield return www.SendWebRequest(); if(www.isNetworkError || www.isHttpError) { Debug.Log(www.error); } else { Debug.Log(www.downloadHandler.text); JSONNode jsonNode = JSON.Parse(www.downloadHandler.text); string title = jsonNode[0]["title"].ToString(); Debug.Log("Title: " + title); } }

For demo: https://github.com/codemaker2015/api-interaction-unity3d-demo

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