2 min read

HTTP Streaming Using Go

HTTP Streaming Using Go

As I continue adding features to Cortex I needed to connect to the streaming api that Flowdock provides.

A quick Google search took me to this post which shows how to do that. It works, but while I was reading the code, it looked pretty low level for my taste. So I decided to try and use the http package.

Making the initial request

url := "https://stream.flowdock.com/flows?filter=fmpwizard/mission-control"
token := []byte(flowdockAccessToken) //used by Flowdock
str := base64.StdEncoding.EncodeToString(token) //used by Flowdock
req, _ := http.NewRequest("GET", url, nil) // This will be a GET request
req.Header.Add("Authorization", fmt.Sprintf("Basic %s", str)) //Add the base64 encoded token
client := &http.Client{}
res, err := client.Do(req) // Do the actual HTTP GET request

if err != nil {
defer res.Body.Close() //Close the body once we are done.

So far this looks like any other GET request that needs some specific header to be added. What is different when dealing with a stream is how you read the partial body.

Reading the body, line by line.

for {
    line, _ := reader.ReadBytes('\r') // we read until the carriage return, this may be diff on other streaming apis
    line = bytes.TrimSpace(line)
    jsonString := string(line[:])
    log.Printf("String: %v\n\n", jsonString)
    ... //Do anything you want to with the line you just got, in my case I parse the json data
        //into some struct and then I send it to [wit.ai](http://wit.ai)

And that’s it, pretty simple.

Thank you for reading.

Diego @fmpwizard

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