How to use google speech recognition api in c#?

Question

I want to get the audio file from c# and send to google speech recognition API for get the "speech to text" answer.

My code is like this:

try
{                
    byte[] BA_AudioFile = GetFile(filename);              
    HttpWebRequest _HWR_SpeechToText = null;
    _HWR_SpeechToText =
                (HttpWebRequest)HttpWebRequest.Create(
                    "https://www.google.com/speech-api/v2/recognize?output=json&lang=" + DEFAULT_LANGUAGE + "&key=" + key);
    _HWR_SpeechToText.Credentials = CredentialCache.DefaultCredentials;
    _HWR_SpeechToText.Method = "POST";
    _HWR_SpeechToText.ContentType = "audio/x-flac; rate=44100";
    _HWR_SpeechToText.ContentLength = BA_AudioFile.Length;
    Stream stream = _HWR_SpeechToText.GetRequestStream();
    stream.Write(BA_AudioFile, 0, BA_AudioFile.Length);
    stream.Close();

    HttpWebResponse HWR_Response = (HttpWebResponse)_HWR_SpeechToText.GetResponse();
    if (HWR_Response.StatusCode == HttpStatusCode.OK)
    {
        StreamReader SR_Response = new StreamReader(HWR_Response.GetResponseStream());
        Console.WriteLine(SR_Response.ToString());
    }

}
catch (Exception ex)
{
    Console.WriteLine(ex.ToString());
}

This part is for upload the file.wav and get the response for the google API, which I find from Internet.

But my code always catches the exceptions:

you must write content length bytes to the request stream before calling at _HWR_SpeechToText.GetResponse(); But I already wroteh the ContextLength.

So my question is why my program failed? It's because the google link or the HTTPWebRequest I used inappropriately?

Is this the right place I got the API key?

Solution

Just tested this myself, below is a working solution if you have a valid API key.

    using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Text;
    using System.Threading.Tasks;
    using System.Net;
    using System.IO;

    namespace GoogleRequest
    {
     class Program
     {
        static void Main(string[] args)
        {
            try
            {

                FileStream fileStream = File.OpenRead("good-morning-google.flac");
                MemoryStream memoryStream = new MemoryStream();
                memoryStream.SetLength(fileStream.Length);
                fileStream.Read(memoryStream.GetBuffer(), 0, (int)fileStream.Length);
                byte[] BA_AudioFile = memoryStream.GetBuffer();
                HttpWebRequest _HWR_SpeechToText = null;
                _HWR_SpeechToText =
                            (HttpWebRequest)HttpWebRequest.Create(
                                "https://www.google.com/speech-api/v2/recognize?output=json&lang=en-us&key=YOUR_API_KEY_HERE");
                _HWR_SpeechToText.Credentials = CredentialCache.DefaultCredentials;
                _HWR_SpeechToText.Method = "POST";
                _HWR_SpeechToText.ContentType = "audio/x-flac; rate=44100";
                _HWR_SpeechToText.ContentLength = BA_AudioFile.Length;
                Stream stream = _HWR_SpeechToText.GetRequestStream();
                stream.Write(BA_AudioFile, 0, BA_AudioFile.Length);
                stream.Close();

                HttpWebResponse HWR_Response = (HttpWebResponse)_HWR_SpeechToText.GetResponse();
                if (HWR_Response.StatusCode == HttpStatusCode.OK)
                {
                    StreamReader SR_Response = new StreamReader(HWR_Response.GetResponseStream());
                    Console.WriteLine(SR_Response.ReadToEnd());
                }

            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.ToString());
            }

            Console.ReadLine();
        }
    }
}

Comments

[Nikolay Shmyrev]

How big is your file? Did you try with a smaller one?

[cindywmiao]

@NikolayShmyrev I test the file from github.com/gillesdemey/google-speech-v2

[Nikolay Shmyrev]

Which file exactly, there are 3 of them in audio folder

[Nikolay Shmyrev]

Also, do you really have / after rate line in your code?

[cindywmiao]

@NikolayShmyrev good-morning-google.flac, and I try the other two, it's the same.

[SimpleVar]

Have you tried not setting the content length? From what I understand, it is set automatically when you write to the request stream anyways. Maybe manually setting it beforehand messes it up. (By the way, you should really hide vulnerable information like your API key, email, etc - I took the liberty to do it here)

[Muhammad Faizan Khan]

@cindywmiao I am unable to run how did you validated your API key? i guess m facing same error

[cindywmiao]

Still, the same exception as the old code. I could not get _HWR_SpeechToText.GetResponse()

[cindywmiao]

The remote server returned an error: (403) Forbidden.

[cindywmiao]

Hello, could you check out is the right place I got the google API key? I have add the key in my question.

[Umo]

Yes, the key for server applications is the right one, but you have to enable the Speech API aswell, the option to do should be under API's & Auth --> APIs. I see that you have a IP specified aswell, and i seems to be a private one, try removing any IP and it should allow access from any IP

[cindywmiao]

I think my key has some problem. so I find one from internet. It passed buut I got nothing in the response.

[Umo]

@cindywmiao Updated my answer again and here is a link to the whole project, your should be about to download, add your API key and just run it to see the response. link to project

[cindywmiao]

I still think the problem comes from the API key. Because I use my key, it give me an exception, I find one other key from Internet, it give me nothing. I use your code, it's the same thing.

[Umo]

You need to subscribe as a chromium dev aswell i think, i followed the instructions on this site, otherwise you cant activate the right api in the developer console and your key wont work. chromium.org/developers/how-tos/api-keys

[Sanju Rao]

@Umo I get the out put as only {"result":[]}. I don see any output result. I have used the same code that is here. Can you please help me if i am missing to do anything extra?

[Alex Choroshin]

I'm still getting 403, can anyone help?

[Alex Choroshin]

@SanjuRao have you succeeded getting any output? I'm still getting 403 error.

[Sanju Rao]

@AlexChoroshin yes.

[Alex Choroshin]

@SanjuRao , after generating a key in google cloud platform, I still getting the 403 error, can you please assist?

[Sanju Rao]

@AlexChoroshin I may need time to go back to my repository to see the solution give me some time. I will get back to u on this.

[Muhammad Faizan Khan]

@Umo you code is not working and showing error on repsonse line that "The underlying connection was closed: An unexpected error occurred on a receive."

[Muhammad Faizan Khan]

getting error stackoverflow.com/questions/40254879/…