无需SDK的Amazon Transcribe流API [英] Amazon Transcribe Streaming API without SDK
问题描述
我正在尝试使用Go 1.11中的亚马逊新的流式转录API.目前，亚马逊仅提供Java SDK，因此我正在尝试低级方式.
I am trying to use Amazon's new streaming transcribe API from Go 1.11. Currently Amazon provides Java SDK only so I am trying the low-level way.
唯一相关的文档是此处，但是它不显示端点.我已经在
The only relevant piece of documentation is here but it does not show the endpoint. I have found it in a Java example that it is https://transcribestreaming.<region>.amazonaws.com and I am trying the Ireland region i.e. https://transcribestreaming.eu-west-1.amazonaws.com. Here is my code to open an HTTP/2 bi-directional stream:
import (
"crypto/tls"
"github.com/aws/aws-sdk-go-v2/aws"
"github.com/aws/aws-sdk-go-v2/aws/external"
"github.com/aws/aws-sdk-go-v2/aws/signer/v4"
"golang.org/x/net/http2"
"io"
"io/ioutil"
"log"
"net/http"
"os"
"time"
)
const (
HeaderKeyLanguageCode = "x-amzn-transcribe-language-code" // en-US
HeaderKeyMediaEncoding = "x-amzn-transcribe-media-encoding" // pcm only
HeaderKeySampleRate = "x-amzn-transcribe-sample-rate" // 8000, 16000 ... 48000
HeaderKeySessionId = "x-amzn-transcribe-session-id" // For retrying a session. Pattern: [a-fA-F0-9]{8}-[a-fA-F0-9]{4}-[a-fA-F0-9]{4}-[a-fA-F0-9]{4}-[a-fA-F0-9]{12}
HeaderKeyVocabularyName = "x-amzn-transcribe-vocabulary-name"
HeaderKeyRequestId = "x-amzn-request-id"
)
...
region := "eu-west-1"
cfg, err := external.LoadDefaultAWSConfig(aws.Config{
Region: region,
})
if err != nil {
log.Printf("could not load default AWS config: %v", err)
return
}
signer := v4.NewSigner(cfg.Credentials)
transport := &http2.Transport{
TLSClientConfig: &tls.Config{
// allow insecure just for debugging
InsecureSkipVerify: true,
},
}
client := &http.Client{
Transport: transport,
}
signTime := time.Now()
header := http.Header{}
header.Set(HeaderKeyLanguageCode, "en-US")
header.Set(HeaderKeyMediaEncoding, "pcm")
header.Set(HeaderKeySampleRate, "16000")
header.Set("Content-type", "application/json")
// Bi-directional streaming via a pipe.
pr, pw := io.Pipe()
req, err := http.NewRequest(http.MethodPost, "https://transcribestreaming.eu-west-1.amazonaws.com/stream-transcription", ioutil.NopCloser(pr))
if err != nil {
log.Printf("err: %+v", err)
return
}
req.Header = header
_, err = signer.Sign(req, nil, "transcribe", region, signTime)
if err != nil {
log.Printf("problem signing headers: %+v", err)
return
}
// This freezes and ends after 5 minutes with "unexpected EOF".
res, err := client.Do(req)
...
问题是执行请求(client.Do(req))会冻结五分钟，然后以意外的EOF"错误结束.
Problem is that executing the request (client.Do(req)) freezes for five minutes and then ends with the "unexpected EOF" error.
有什么想法我做错了吗?有人在没有Java SDK的情况下成功使用了新的流式转录API吗?
Any ideas what I am doing wrong? Did someone successfully use the new streaming transcribe API without the Java SDK?
编辑(2019年3月11日):
我再次对此进行了测试，现在它没有超时，但立即返回200 OK响应.响应正文中有一个例外":{"Output":{"__type":"com.amazon.coral.service#SerializationException"},"Version":"1.0"}
I tested this again and now it does not time out but immediately returns 200 OK response. There is an "exception" in the response body though: {"Output":{"__type":"com.amazon.coral.service#SerializationException"},"Version":"1.0"}
我尝试使用io.Pipe(如上面的代码)以及文档中描述的JSON正文打开HTTP2流:
I tried opening the HTTP2 stream with io.Pipe (like the code above) and also with a JSON body described in the documentation:
{
"AudioStream": {
"AudioEvent": {
"AudioChunk": ""
}
}
}
结果是相同的.
编辑(2019年3月13日):
如@gpeng所述，从标题中删除content-type将修复SerializationException.但是然后有一个IAM异常，需要将transcription:StartStreamTranscription权限添加到您的IAM用户.虽然在AWS IAM控制台中没有任何地方，但必须作为自定义JSON权限手动添加:/
As mentioned by @gpeng, removing the content-type from headers will fix the SerializationException. But then there is an IAM exception and it is needed to add the transcription:StartStreamTranscription permission to your IAM user. That is though nowhere in the AWS IAM console and must be added manually as a custom JSON permission :/
此处，其中显示了错误的host和新的content-type(请勿使用该content-type，请求将返回404).
There is also a new/another documentation document here which shows incorrect host and a new content-type (do not use that content-type, the request will return 404 with it).
删除content-type，并添加新的权限后，现在我得到了异常{"Message":"A complete signal was sent without the preceding empty frame."}.还要永久写入管道块，所以我又被卡住了.新文档中描述的消息与旧文档中的消息有所不同，现在是最终的二进制文件，但是我不理解它们.有什么想法如何在Go中发送这样的HTTP2消息吗?
After removing the content-type, and adding the new permission, now I am getting an exception {"Message":"A complete signal was sent without the preceding empty frame."}. Also writing to the pipe blocks forever, so I am stuck again. The messages described in the new documentation are different than in the old one, now finally binary, but I do not understand them. Any ideas how to send such HTTP2 messages in Go?
编辑(2019年15月15日):*
如果收到有关签名不匹配的HTTP 403错误，请不要设置transfer-encoding和x-amz-content-sha256 HTTP标头.设置它们后，请使用AWS开发工具包的V4签名者对请求进行签名，然后收到HTTP 403 The request signature we calculated does not match the signature you provided.
If you get HTTP 403 error about signature mismatch, then do not set the transfer-encoding and x-amz-content-sha256 HTTP headers. When I set them, sign the request with AWS SDK's V4 signer, then I receive HTTP 403 The request signature we calculated does not match the signature you provided.
推荐答案
我寻求AWS支持，他们现在建议尽可能使用websocket而不是HTTP/2(博客文章
I reached out to AWS support and they now recommend using websockets instead of HTTP/2 when possible (blog post here)
如果适合您的用例，我强烈建议您在以下位置查看新的示例存储库:
If this fits your usecase I would highly recommend checking out the new example repo at: https://github.com/aws-samples/amazon-transcribe-websocket-static which shows a browser-based solution in JS.
我还注意到，演示的作者在其个人Github上有一个明确的示例，网址为:
I've also noticed that the author of the demo has an express example on his personal Github at: https://github.com/brandonmwest/amazon-transcribe-websocket-express but I haven't confirmed if this is working.
赞赏这些示例不是在Python中实现的，但我认为使用Websocket客户端而不是HTTP/2会更好(幸运的是，这仍然有点可怕:P)
Appreciate these examples aren't in Python but I think you'll have better luck using the Websocket client as opposed to HTTP/2 (which let's be honest, is still a bit terrifying :P)
这篇关于无需SDK的Amazon Transcribe流API的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
