waku-org/go-waku

package rest

import (
    "encoding/json"
    "fmt"
    "net/http"
    "net/url"

    "github.com/go-chi/chi/v5"
    "go.uber.org/zap"
)

// The functions writes error response in plain text format with specified statusCode
func writeErrResponse(w http.ResponseWriter, log *zap.Logger, err error, statusCode int) {
    w.WriteHeader(statusCode)
    _, err = w.Write([]byte(err.Error()))
    if err != nil {
        log.Error("error while writing response", zap.Error(err))
    }
}

// This function writes error or response in json format with statusCode as 500 in case of error
func writeErrOrResponse(w http.ResponseWriter, err error, value interface{}) {
    w.Header().Set("Content-Type", "application/json; charset=UTF-8")

    if err != nil {
        w.WriteHeader(http.StatusInternalServerError)
        return
    }

    jsonResponse, err := json.Marshal(value)
    if err != nil {
        w.WriteHeader(http.StatusInternalServerError)
        return
    }

    _, err = w.Write(jsonResponse)
    if err != nil {
        w.WriteHeader(http.StatusInternalServerError)
        return
    }
}

// This function writes a response in json format
func writeResponse(w http.ResponseWriter, value interface{}, code int) {
    w.Header().Set("Content-Type", "application/json; charset=UTF-8")
    jsonResponse, err := json.Marshal(value)
    if err != nil {
        w.WriteHeader(http.StatusInternalServerError)
        return
    }

    // w.Write implicitly writes a 200 status code
    // and only once we can write 2xx-5xx status code
    // so any statusCode apart from 1xx being written to the header, will be ignored.
    w.WriteHeader(code)
    _, _ = w.Write(jsonResponse)
}

func topicFromPath(w http.ResponseWriter, req *http.Request, field string, logger *zap.Logger) string {
    topic := chi.URLParam(req, field)
    if topic == "" {
        errMissing := fmt.Errorf("missing %s", field)
        writeGetMessageErr(w, errMissing, http.StatusBadRequest, logger)
        return ""
    }
    topic, err := url.QueryUnescape(topic)
    if err != nil {
        errInvalid := fmt.Errorf("invalid %s format", field)
        writeGetMessageErr(w, errInvalid, http.StatusBadRequest, logger)
        return ""
    }
    return topic
}

func writeGetMessageErr(w http.ResponseWriter, err error, code int, logger *zap.Logger) {
    // write status before the body
    w.WriteHeader(code)
    logger.Error("get message", zap.Error(err))
    if _, err := w.Write([]byte(err.Error())); err != nil {
        logger.Error("writing response", zap.Error(err))
    }
}