Menu
I am trying to post audio data with curl for a HTTP-API which allows to transmit/receive audio files.
First I tried this:
curl -vv --http1.0 -H "Content-Type: audio/basic" -H "Content-Length: 9999999" -H "Connection: Keep-Alive" -H "Cache-Control: no-cache" --data-binary @- 'http://IP/API-Endpoint.cgi'
This seems to work:
* Trying [IP]...
* TCP_NODELAY set
* Connected to [IP] ([IP]) port 80 (#0)
> POST /API-Endpoint.cgi HTTP/1.0
> Host: [IP]
> User-Agent: curl/7.54.0
> Accept: */*
> Content-Type: audio/basic
> Content-Length: 9999999
> Connection: Keep-Alive
> Cache-Control: no-cache
>
* upload completely sent off: 17456 out of 17456 bytes
* HTTP 1.0, assume close after body
< HTTP/1.0 200 OK
< Content-Type: text/plain
< Content-Length: 0
* HTTP/1.0 connection set to keep alive!
< Connection: keep-alive
< Date: Wed, 06 Jun 2018 19:38:37 GMT
< Server: lighttpd/1.4.45
But I can only hear the very last part of the Audio file. (The file has the correct audio format for the API: G.711 μ-law with 8000 Hz) My next guess is, that the audio gets transmitted too fast and has to be sent in real time to the API endpoint. So I tried the --limit-rate parameter of curl, which had no effect. Then I tried piping the data with a rate limit into curl:
cat myfile.wav | pv -L 10k | curl -vv --http1.0 -H "Content-Type: audio/basic" -H "Content-Length: 9999999" -H "Connection: Keep-Alive" -H "Cache-Control: no-cache" --data-binary @- 'http://IP/API-Endpoint.cgi'
but the result is always the same: I can only hear the last part of the audio file. It seems like curl is waiting for the piped input to complete and then sends the request as before.
Is there an option to post audio to a HTTP-API from bash in "real time"?
Update: Without forcing HTTP 1.0 I get the following result:
curl -vv -H "Content-Type: audio/basic" --data-binary '@myfile.wav' 'http://[IP]/API-Endpoint.cgi'
* Trying [IP]...
* TCP_NODELAY set
* Connected to [IP] ([IP]) port 80 (#0)
> POST /API-Endpoint.cgi HTTP/1.1
> Host: [IP]
> User-Agent: curl/7.54.0
> Accept: */*
> Content-Type: audio/basic
> Content-Length: 15087
> Expect: 100-continue
>
< HTTP/1.1 417 Expectation Failed
< Content-Type: text/html
< Content-Length: 363
< Connection: close
< Date: Wed, 06 Jun 2018 20:34:22 GMT
< Server: lighttpd/1.4.45
<
<?xml version="1.0" encoding="iso-8859-1"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<title>417 - Expectation Failed</title>
</head>
<body>
<h1>417 - Expectation Failed</h1>
</body>
</html>
* Closing connection 0
650
with -H "Content-Length: 9999999" you say that your audio file is exactly 9999999 bytes long (roughly 10 megabytes), but curl reports that your file is 17456 bytes:
* upload completely sent off: 17456 out of 17456 bytes
(roughly 0.02 megabytes), so either your Content-Length header is wrong (that's my best guess), or the program feeding your audio file to curl is faulty, closing stdin prematurely.
either fix your Content-Length header, or fix the program feeding curl's stdin, hopefully that should send the entire file intact.
EDIT: oh, seems that server can't handle Expect: 100-continue, to disable that header, add the argument -H 'Expect:'
(an empty Expect header will make curl omit the header entirely, instead of sending the header empty)
... but to answer the question in the title, yeah that's the --limit-rate argument.
165
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
