How to pass parameters by POST to an Azure function?

user_1781663 0
Viewed 122111

I'm trying to do a simple Azure Function to learn about it. There will be 3 functions:

  • 1 function to insert a row into a table of a database. This table will contain the current date and a string parameters typed by the user and passed by GET.
  • 1 function similar to the previous one, but passing the parameter by POST.
  • 1 function to read the table and show its content.

I've been able to do the first and the third ones. But I can't pass the parameter by POST. I've looked for examples but I couldn't run them with success. The client app is a Windows Forms one.

Could anyone show me an example anout how to pass parameters by POST to the function and how to read them?

Thank's in advance

EDIT:

Here's the code to pass the parameters by GET (this is working fine):

private void button2_Click(object sender, EventArgs e)
{
    string cadena = lsql1.Text + "?notas=" + tNotas.Text;

    try
    {
        HttpWebRequest req = (HttpWebRequest)WebRequest.Create(cadena);
        HttpWebResponse res = (HttpWebResponse)req.GetResponse();

        if (res.StatusCode == HttpStatusCode.OK)
        {
            MessageBox.Show("Grabado");
        }
        else
        {
            MessageBox.Show(res.StatusDescription);
        }
    }catch (WebException ex)
    {
        using (Stream s = ex.Response.GetResponseStream())
        {
            StreamReader sr = new StreamReader(s);
            string text = sr.ReadToEnd();
            text = text.Substring(1, text.Length - 2);
            sr.Close();
            text = text.Replace("\\", "");
            text = "{" + text + "}";
            Error mensajeError = JsonConvert.DeserializeObject<Error>(text);

            MessageBox.Show(mensajeError.ExceptionMessage);
        }

    }
}

And here's the code to receive it and do the insert (this is working too):

[FunctionName("sql1")]
public static async Task<HttpResponseMessage> Run(HttpRequestMessage req, TraceWriter log)
{
    try
    {
        log.Info("C# HTTP trigger function processed a request.");

        var cnnString = "Server=SERVIDOR;Database=base_prueba;User ID =azure;Password=0000;Trusted_Connection=False;Encrypt=False;";

        using (SqlConnection connection = new SqlConnection(cnnString))
        {
            connection.Open();
            SqlCommand cmd = connection.CreateCommand();

            DateTime fecha = DateTime.Today;

            string notas = req.GetQueryNameValuePairs()
            .FirstOrDefault(q => string.Compare(q.Key, "notas", true) == 0)
            .Value;

            // insert a log to the database
            cmd.CommandText = "INSERT INTO Prueba_Azure (fecha, notas) VALUES ('" + fecha.ToString() + "', '" + notas + "')";
            cmd.ExecuteNonQuery();
        }

        // Get request body
        dynamic data = await req.Content.ReadAsAsync<object>();

        return name == req.CreateResponse(HttpStatusCode.OK, "Done");
    }
    catch (Exception ex)
    {
        HttpResponseMessage res = req.CreateErrorResponse(HttpStatusCode.InternalServerError, ex);
        return res;
    }
}

What I'm looking for is to to this by POST

azure-functions azure post visual-studio c#
11 Answers

In case google took you here, this is how it's done in March 2019 (Azure Functions v3):

public static async void Run(
            [HttpTrigger(AuthorizationLevel.Function, "post", Route = null)]
            HttpRequest req,
            ILogger log)
        {
            var content = await new StreamReader(req.Body).ReadToEndAsync();

            MyClass myClass = JsonConvert.DeserializeObject<MyClass>(content);
            
        }
user_16751280

If you are using System.Text.Json, you can read the POST data in one line:

public static async Task Run(
    [HttpTrigger(AuthorizationLevel.Function, "post", Route = null)]
    HttpRequest req,
    ILogger log)
{
    MyClass myClass = await JsonSerializer.DeserializeAsync<MyClass>(req.Body);
}

If you are using Newtonsoft.Json, see the answer by Allen Zhang.

user_10636180

You can just supply your custom data class as a parameter to the HttpTrigger argument. This way you don't have to mess with the json deserialization yourself:

public async Task<IActionResult> UpdateAccount(
        [HttpTrigger(AuthorizationLevel.Anonymous, "post", Route = "api/v1/accounts/{id:guid}")] 
        SomeData someData,  // <----- Post body ends up here automatically
        HttpRequest req,
        Guid id,
        ILogger log)
{
    log.LogInformation ("Got POST with " + someData.Foo);
}


public class SomeData
{
    public string Foo { get; set; } = null!;
}
user_533280

It can be done in following way with custom class

Azure Function 

[FunctionName("PostParameterFunction")]
public static async Task<HttpResponseMessage> Run([HttpTrigger(AuthorizationLevel.Anonymous, "get", "post", Route = null)]HttpRequestMessage req, ILogger log)
   {
      log.LogInformation("C# HTTP trigger function processed a request.");

       try
        {
             // Convert all request perameter into Json object

                var content = req.Content;
                string jsonContent = content.ReadAsStringAsync().Result;
                dynamic requestPram = JsonConvert.DeserializeObject<RequestModel>(jsonContent);

                // Validate the required param

                if (string.IsNullOrEmpty(requestPram.FirstName))
                {
                    return req.CreateResponse(HttpStatusCode.OK, "Please enter First Name!");
                }
                if (string.IsNullOrEmpty(requestPram.LastName))
                {
                    return req.CreateResponse(HttpStatusCode.OK, "Please enter Last Name!");
                }


                //Create object for partner Model to bind the response on it

                RequestModel objRequestModel = new RequestModel();

                objRequestModel.FirstName = requestPram.FirstName;
                objRequestModel.LastName = requestPram.LastName;

                //Return Request Model

                return req.CreateResponse(HttpStatusCode.OK, objRequestModel);
         }
        catch (Exception ex)
         {

                return req.CreateResponse(HttpStatusCode.OK, "Cannot Create Request! Reason: {0}", string.Format(ex.Message));
         }

        }

Request Class:

 public class RequestModel
    {
        public string FirstName { get; set; }
        public string LastName { get; set; }

    }

Request Input:

{
    "FirstName": "Kiron",
    "LastName":"Test"
}

PostMan Output Example:

enter image description here

user_96630700

I have done a very simple example to get data using POST request in Azure Function App. Please find the following example.

using System;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Threading.Tasks;
using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Extensions.Http;
using Microsoft.Azure.WebJobs.Host;

namespace MyFunctions
{
    public static class MyFunctionsOperations
    {
        [FunctionName("MyFunctionsOperations")]
        public static async Task<HttpResponseMessage> Run([HttpTrigger(AuthorizationLevel.Function, "post", Route = null)]HttpRequestMessage req, TraceWriter log)
        {
            log.Info("C# HTTP trigger function processed a request.");
            var headers = req.Headers;
            string collection = headers.GetValues("collection").First();   //getting parameter from header

            CosmosdbOperation obj = new CosmosdbOperation();
            dynamic data = await req.Content.ReadAsAsync<object>();  //getting body content
            Boolean response = await obj.MyFunctionExecution(data.ToString(), collection);

            return (response)
                ? req.CreateResponse(HttpStatusCode.BadRequest, "Please pass a proper argument in the request body")
                : req.CreateResponse(HttpStatusCode.OK, "Operation successfully executed..");
        }
    }
}
user_7462700

I like the WebApi approach of using [FromBody] attribute, so using IBinding I made my own. Now I can just pass in the object.

[AttributeUsage(AttributeTargets.Parameter | AttributeTargets.ReturnValue)]
[Binding]
public sealed class FromBodyAttribute : Attribute
{
}

public class FromBodyBinding : IBinding
{
    private readonly ILogger logger;
    public FromBodyBinding(ILogger logger)
    {
        this.logger = logger;
    }
    public Task<IValueProvider> BindAsync(BindingContext context)
    {
        // Get the HTTP request
        var request = context.BindingData["req"] as DefaultHttpRequest;

        return Task.FromResult<IValueProvider>(new FromBodyValueProvider(request, logger));
    }

    public bool FromAttribute => true;


    public Task<IValueProvider> BindAsync(object value, ValueBindingContext context)
    {
        return null;
    }

    public ParameterDescriptor ToParameterDescriptor() => new ParameterDescriptor();
}

public class FromBodyBindingProvider : IBindingProvider
{
    private readonly ILogger logger;
    public FromBodyBindingProvider(ILogger logger)
    {
        this.logger = logger;
    }

    public Task<IBinding> TryCreateAsync(BindingProviderContext context)
    {
        IBinding binding = new FromBodyBinding(this.logger);
        return Task.FromResult(binding);
    }
}

public class FromBodyValueProvider : IValueProvider
{
    private HttpRequest request;
    private ILogger logger;

    public FromBodyValueProvider(HttpRequest request, ILogger logger)
    {
        this.request = request;
        this.logger = logger;
    }

    public async Task<object> GetValueAsync()
    {
        try
        {
            string requestBody = await new StreamReader(this.request.Body).ReadToEndAsync();
            object result = JsonConvert.DeserializeObject(requestBody);
            return result;
        }
        catch (System.Exception ex)
        {
            this.logger.LogCritical(ex, "Error deserializing object from body");

            throw ex;
        }
    }

    public Type Type => typeof(object);

    public string ToInvokeString() => string.Empty;
}

public class BindingExtensionProvider : IExtensionConfigProvider
{
    private readonly ILogger logger;
    public BindingExtensionProvider(ILogger<Startup> logger)
    {
        this.logger = logger;
    }

    public void Initialize(ExtensionConfigContext context)
    {
        // Creates a rule that links the attribute to the binding
        context.AddBindingRule<FromBodyAttribute>().Bind(new FromBodyBindingProvider(this.logger));
    }
}

Then inside your Startup.cs file, add the binding.

public class Startup : IWebJobsStartup
{
    public void Configure(IWebJobsBuilder builder)
    {
        JsonConvert.DefaultSettings = () =>
        {
            return new JsonSerializerSettings()
            {
                ContractResolver = new DefaultContractResolver
                {
                    NamingStrategy = new CamelCaseNamingStrategy()
                },
                Formatting = Formatting.Indented
            };
        };

        builder.Services.AddLogging();
        builder.AddExtension<BindingExtensionProvider>();

    }
}

Now you can just have a regular old class, just like WebApi!

[FunctionName("MyFunction")]
public async Task<IActionResult> Run(
    [HttpTrigger(AuthorizationLevel.Anonymous, "post", Route = null)] HttpRequest req,
    [Binding.FromBody] dynamic data) // or you can change 'dynamic' to some class
{
    string username = data?.username;
    ...
}
user_1589580

Here is the point --> https://docs.microsoft.com/en-us/azure/azure-functions/functions-bindings-http-webhook-trigger?tabs=in-process%2Cfunctionsv2&pivots=programming-language-csharp

    [FunctionName("LuckyNumber")]
    public static async Task<IActionResult> Run(
        [HttpTrigger(
        AuthorizationLevel.Function,
        "get", "post",
        Route = "max/{max:int?}/min/{min:int?}")] HttpRequest req,
        int? max, <-- Parameter max
        int? min, <-- Parameter min
        ILogger log)
    {
        int? maxInternal = max;
        int? minInternal = min;
    }

PS: I´m using .NET 6

user_81047550
Related