jsonenums/server/server.go

125 lines
3.1 KiB
Go

// Copyright 2017 Google Inc. All rights reserved.
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to writing, software distributed
// under the License is distributed on a "AS IS" BASIS, WITHOUT WARRANTIES OR
// CONDITIONS OF ANY KIND, either express or implied.
//
// See the License for the specific language governing permissions and
// limitations under the License.
// Server is an http server that provides an alternative way of generating code
// based on int types and the constants defined with it.
//
// Use the http flag to change the address on which the server will listen for
// requests. The default is 127.0.0.1:8080.
package main
import (
"bytes"
"fmt"
"io/ioutil"
"log"
"net/http"
"os"
"path/filepath"
"text/template"
"go/format"
"github.com/campoy/jsonenums/parser"
)
func init() {
http.Handle("/generate", handler(generateHandler))
}
func generateHandler(w http.ResponseWriter, r *http.Request) error {
if r.Method != "GET" {
return codeError{fmt.Errorf("only GET accepted"), http.StatusMethodNotAllowed}
}
code := r.FormValue("code")
if code == "" {
return codeError{fmt.Errorf("no code to be parsed"), http.StatusBadRequest}
}
typ := r.FormValue("type")
if typ == "" {
return codeError{fmt.Errorf("no type to be analyzed"), http.StatusBadRequest}
}
dir, err := createDir(code)
if err != nil {
return err
}
defer os.RemoveAll(dir)
pkg, err := parser.ParsePackage(dir)
if err != nil {
return fmt.Errorf("parse package: %v", err)
}
values, err := pkg.ValuesOfType(typ)
if err != nil {
return fmt.Errorf("find values: %v", err)
}
t, err := template.New("code").Parse(r.FormValue("template"))
if err != nil {
return codeError{fmt.Errorf("parse template: %v", err), http.StatusBadRequest}
}
var data = struct {
PackageName string
TypeName string
Values []string
}{pkg.Name, typ, values}
var buf bytes.Buffer
if err := t.Execute(&buf, data); err != nil {
return codeError{fmt.Errorf("execute template: %v", err), http.StatusBadRequest}
}
src, err := format.Source(buf.Bytes())
if err != nil {
return codeError{fmt.Errorf("code generated is not valid: %v\n%v", err, buf.String()), http.StatusBadRequest}
}
w.Write(src)
return nil
}
func createDir(content string) (string, error) {
dir, err := ioutil.TempDir("", "jsonenums")
if err != nil {
return "", fmt.Errorf("create tmp dir: %v", err)
}
f, err := os.Create(filepath.Join(dir, "main.go"))
if err != nil {
os.RemoveAll(dir)
return "", fmt.Errorf("create tmp file: %v", err)
}
f.WriteString(content)
f.Close()
return dir, err
}
type handler func(http.ResponseWriter, *http.Request) error
func (h handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
err := h(w, r)
if err != nil {
code := http.StatusInternalServerError
if cErr, ok := err.(codeError); ok {
code = cErr.code
} else {
log.Printf("%v: %v", r.URL, code)
}
http.Error(w, err.Error(), code)
}
}
type codeError struct {
error
code int
}