json - gzip compression to http responseWriter -
i'm new go. playing rest api. cant same behavior out of json.marshal json.encoder in 2 functions have
i wanted use function gzip responses:
func gzipfast(a *[]byte) []byte { var b bytes.buffer gz := gzip.newwriter(&b) defer gz.close() if _, err := gz.write(*a); err != nil { panic(err) } return b.bytes() } but function returns this:
curl http://localhost:8081/compressedget --compressed --verbose * trying 127.0.0.1... * connected localhost (127.0.0.1) port 8081 (#0) > /compressedget http/1.1 > host: localhost:8081 > user-agent: curl/7.47.0 > accept: */* > accept-encoding: deflate, gzip > < http/1.1 200 ok < content-encoding: gzip < content-type: application/json < date: wed, 24 aug 2016 00:59:38 gmt < content-length: 30 < * connection #0 host localhost left intact here go function:
func compressedget(w http.responsewriter, r *http.request, ps httprouter.params) { box := box{width: 10, height: 20, color: "gree", open: false} box.ars = make([]int, 100) := range box.ars { box.ars[i] = } //fmt.println(r.header.get("content-encoding")) w.header().set("content-type", "application/json") w.header().set("content-encoding", "gzip") b, _ := json.marshal(box) //fmt.println(len(b)) //fmt.println(len(gzipfast(&b))) fmt.fprint(w, gzipfast(&b)) //fmt.println(len(gzipslow(b))) //gz := gzip.newwriter(w) //defer gz.close() //json.newencoder(gz).encode(box) r.body.close() } but when uncomment:
//gz := gzip.newwriter(w) //defer gz.close() //json.newencoder(gz).encode(box) it works fine.
you need flush or close gzip writer before accessing underlying bytes, e.g.
func gzipfast(a *[]byte) []byte { var b bytes.buffer gz := gzip.newwriter(&b) if _, err := gz.write(*a); err != nil { gz.close() panic(err) } gz.close() return b.bytes() } otherwise what's been buffer in gzip writer, not yet written out final stream isn't getting collected up.
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