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// Copyright 2017 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package http
import (
"encoding/json"
"fmt"
"html/template"
"net/http"
"strings"
"time"
"github.com/ethereum/go-ethereum/log"
"github.com/ethereum/go-ethereum/metrics"
"github.com/ethereum/go-ethereum/swarm/api"
)
//metrics variables
var (
htmlCounter = metrics.NewRegisteredCounter("api.http.errorpage.html.count", nil)
jsonCounter = metrics.NewRegisteredCounter("api.http.errorpage.json.count", nil)
plaintextCounter = metrics.NewRegisteredCounter("api.http.errorpage.plaintext.count", nil)
)
//parameters needed for formatting the correct HTML page
type ResponseParams struct {
Msg template.HTML
Code int
Timestamp string
template *template.Template
Details template.HTML
}
//ShowMultipeChoices is used when a user requests a resource in a manifest which results
//in ambiguous results. It returns a HTML page with clickable links of each of the entry
//in the manifest which fits the request URI ambiguity.
//For example, if the user requests bzz:/<hash>/read and that manifest contains entries
//"readme.md" and "readinglist.txt", a HTML page is returned with this two links.
//This only applies if the manifest has no default entry
func ShowMultipleChoices(w http.ResponseWriter, r *http.Request, list api.ManifestList) {
log.Debug("ShowMultipleChoices", "ruid", GetRUID(r.Context()), "uri", GetURI(r.Context()))
msg := ""
if list.Entries == nil {
RespondError(w, r, "Could not resolve", http.StatusInternalServerError)
return
}
requestUri := strings.TrimPrefix(r.RequestURI, "/")
uri, err := api.Parse(requestUri)
if err != nil {
RespondError(w, r, "Bad Request", http.StatusBadRequest)
}
uri.Scheme = "bzz-list"
//request the same url just with bzz-list
msg += fmt.Sprintf("Disambiguation:<br/>Your request may refer to multiple choices.<br/>Click <a class=\"orange\" href='"+"/"+uri.String()+"'>here</a> if your browser does not redirect you within 5 seconds.<script>setTimeout(\"location.href='%s';\",5000);</script><br/>", "/"+uri.String())
RespondTemplate(w, r, "error", msg, http.StatusMultipleChoices)
}
func RespondTemplate(w http.ResponseWriter, r *http.Request, templateName, msg string, code int) {
log.Debug("RespondTemplate", "ruid", GetRUID(r.Context()), "uri", GetURI(r.Context()))
respond(w, r, &ResponseParams{
Code: code,
Msg: template.HTML(msg),
Timestamp: time.Now().Format(time.RFC1123),
template: TemplatesMap[templateName],
})
}
func RespondError(w http.ResponseWriter, r *http.Request, msg string, code int) {
log.Debug("RespondError", "ruid", GetRUID(r.Context()), "uri", GetURI(r.Context()))
RespondTemplate(w, r, "error", msg, code)
}
//evaluate if client accepts html or json response
func respond(w http.ResponseWriter, r *http.Request, params *ResponseParams) {
w.WriteHeader(params.Code)
if params.Code >= 400 {
w.Header().Del("Cache-Control") //avoid sending cache headers for errors!
w.Header().Del("ETag")
}
acceptHeader := r.Header.Get("Accept")
// this cannot be in a switch form since an Accept header can be in the form of "Accept: */*, text/html, application/xhtml+xml, application/xml;q=0.9, */*;q=0.8"
if strings.Contains(acceptHeader, "application/json") {
if err := respondJSON(w, r, params); err != nil {
RespondError(w, r, "Internal server error", http.StatusInternalServerError)
}
} else if strings.Contains(acceptHeader, "text/html") {
respondHTML(w, r, params)
} else {
respondPlaintext(w, r, params) //returns nice errors for curl
}
}
//return a HTML page
func respondHTML(w http.ResponseWriter, r *http.Request, params *ResponseParams) {
htmlCounter.Inc(1)
log.Debug("respondHTML", "ruid", GetRUID(r.Context()))
err := params.template.Execute(w, params)
if err != nil {
log.Error(err.Error())
}
}
//return JSON
func respondJSON(w http.ResponseWriter, r *http.Request, params *ResponseParams) error {
jsonCounter.Inc(1)
log.Debug("respondJSON", "ruid", GetRUID(r.Context()))
w.Header().Set("Content-Type", "application/json")
return json.NewEncoder(w).Encode(params)
}
//return plaintext
func respondPlaintext(w http.ResponseWriter, r *http.Request, params *ResponseParams) error {
plaintextCounter.Inc(1)
log.Debug("respondPlaintext", "ruid", GetRUID(r.Context()))
w.Header().Set("Content-Type", "text/plain")
strToWrite := "Code: " + fmt.Sprintf("%d", params.Code) + "\n"
strToWrite += "Message: " + string(params.Msg) + "\n"
strToWrite += "Timestamp: " + params.Timestamp + "\n"
_, err := w.Write([]byte(strToWrite))
return err
}
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