api_response.go

标签：int   header   .com   utf-8   his   handle   backward   data   mars   package http_apiimport (    "encoding/json"    "fmt"    "io"    "net/http"    "time"    "github.com/julienschmidt/httprouter"    "github.com/nsqio/nsq/internal/app")type Decorator func(APIHandler) APIHandlertype APIHandler func(http.ResponseWriter, *http.Request, httprouter.Params) (interface{}, error)type Err struct {    Code int    Text string}func (e Err) Error() string {    return e.Text}func acceptVersion(req *http.Request) int {    if req.Header.Get("accept") == "application/vnd.nsq; version=1.0" {        return 1    }    return 0}func PlainText(f APIHandler) APIHandler {    return func(w http.ResponseWriter, req *http.Request, ps httprouter.Params) (interface{}, error) {        code := 200        data, err := f(w, req, ps)        if err != nil {            code = err.(Err).Code            data = err.Error()        }        switch d := data.(type) {        case string:            w.WriteHeader(code)            io.WriteString(w, d)        case []byte:            w.WriteHeader(code)            w.Write(d)        default:            panic(fmt.Sprintf("unknown response type %T", data))        }        return nil, nil    }}func NegotiateVersion(f APIHandler) APIHandler {    return func(w http.ResponseWriter, req *http.Request, ps httprouter.Params) (interface{}, error) {        data, err := f(w, req, ps)        if err != nil {            if acceptVersion(req) == 1 {                RespondV1(w, err.(Err).Code, err)            } else {                // this handler always returns 500 for backwards compatibility                Respond(w, 500, err.Error(), nil)            }            return nil, nil        }        if acceptVersion(req) == 1 {            RespondV1(w, 200, data)        } else {            Respond(w, 200, "OK", data)        }        return nil, nil    }}func V1(f APIHandler) APIHandler {    return func(w http.ResponseWriter, req *http.Request, ps httprouter.Params) (interface{}, error) {        data, err := f(w, req, ps)        if err != nil {            RespondV1(w, err.(Err).Code, err)            return nil, nil        }        RespondV1(w, 200, data)        return nil, nil    }}func Respond(w http.ResponseWriter, statusCode int, statusTxt string, data interface{}) {    var response []byte    var err error    switch data.(type) {    case string:        response = []byte(data.(string))    case []byte:        response = data.([]byte)    default:        w.Header().Set("Content-Type", "application/json; charset=utf-8")        response, err = json.Marshal(struct {            StatusCode int `json:"status_code"`            StatusTxt string `json:"status_txt"`            Data interface{} `json:"data"`        }{            statusCode,            statusTxt,            data,        })        if err != nil {            response = []byte(fmt.Sprintf(`{"status_code":500, "status_txt":"%s", "data":null}`, err))        }    }    w.WriteHeader(statusCode)    w.Write(response)}func RespondV1(w http.ResponseWriter, code int, data interface{}) {    var response []byte    var err error    var isJSON bool    if code == 200 {        switch data.(type) {        case string:            response = []byte(data.(string))        case []byte:            response = data.([]byte)        case nil:            response = []byte{}        default:            isJSON = true            response, err = json.Marshal(data)            if err != nil {                code = 500                data = err            }        }    }    if code != 200 {        isJSON = true        response = []byte(fmt.Sprintf(`{"message":"%s"}`, data))    }    if isJSON {        w.Header().Set("Content-Type", "application/json; charset=utf-8")    }    w.Header().Set("X-NSQ-Content-Type", "nsq; version=1.0")    w.WriteHeader(code)    w.Write(response)}func Decorate(f APIHandler, ds ...Decorator) httprouter.Handle {    decorated := f    for _, decorate := range ds {        decorated = decorate(decorated)    }    return func(w http.ResponseWriter, req *http.Request, ps httprouter.Params) {        decorated(w, req, ps)    }}func Log(l app.Logger) Decorator {    return func(f APIHandler) APIHandler {        return func(w http.ResponseWriter, req *http.Request, ps httprouter.Params) (interface{}, error) {            start := time.Now()            response, err := f(w, req, ps)            elapsed := time.Since(start)            status := 200            if e, ok := err.(Err); ok {                status = e.Code            }            l.Output(2, fmt.Sprintf("%d %s %s (%s) %s",                status, req.Method, req.URL.RequestURI(), req.RemoteAddr, elapsed))            return response, err        }    }}func LogPanicHandler(l app.Logger) func(w http.ResponseWriter, req *http.Request, p interface{}) {    return func(w http.ResponseWriter, req *http.Request, p interface{}) {        l.Output(2, fmt.Sprintf("ERROR: panic in HTTP handler - %s", p))        Decorate(func(w http.ResponseWriter, req *http.Request, ps httprouter.Params) (interface{}, error) {            return nil, Err{500, "INTERNAL_ERROR"}        }, Log(l), V1)(w, req, nil)    }}func LogNotFoundHandler(l app.Logger) http.Handler {    return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {        Decorate(func(w http.ResponseWriter, req *http.Request, ps httprouter.Params) (interface{}, error) {            return nil, Err{404, "NOT_FOUND"}        }, Log(l), V1)(w, req, nil)    })}func LogMethodNotAllowedHandler(l app.Logger) http.Handler {    return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {        Decorate(func(w http.ResponseWriter, req *http.Request, ps httprouter.Params) (interface{}, error) {            return nil, Err{405, "METHOD_NOT_ALLOWED"}        }, Log(l), V1)(w, req, nil)    })}api_response.go标签：int   header   .com   utf-8   his   handle   backward   data   mars   原文地址：http://www.cnblogs.com/zhangboyu/p/7457450.html