我有一个简单的应用程序需要REST API调用来执行CRUD（创建，读取，更新，删除）。但是，我似乎无法使REST API正常工作。
当它执行put操作时，我正在
“api.js：81 Uncaught（在promise中）SyntaxError：JSON输入的意外结束 在callAPI（api.js：81）“
我正在使用Api.js检查API调用。
API-photos.js
//photos.js
var express = require('express');
var router = express.Router();
var multer = require('multer');
var photoController = require('../../controllers/photoController');
var upload = multer({
storage: photoController.storage,
fileFilter: photoController.imageFilter
});
//import PhotoService
const PhotoService = photoController.PhotoService;
router.use((req, res, next)=>{
//set mime type for all request and origin
res.set({
'Access-Control-Allow-Origin':'*',
'Access-Control-Allow-Methods':'GET,PUT,POST,DELETE,OPTIONS',
"Access-Control-Allow-Headers":"Content-Type, Access-Control-Allow-Headers",
'Content-type':'applicaion/json'
});
if(req.method == 'OPTIONS'){
return res.status(200).end();
}
next();
})
// photos - list
router.get('/', (req, res, next)=>{
PhotoService.list()
//returns promise - argument passed photos
.then((photos)=>{
console.log(`API: Found images: ${photos}`);
res.status(200);
//set content type header to application/json - set correct mime type
res.send(JSON.stringify(photos));
});
})
// photos/:photoid - find
router.get('/:photoid', (req, res, next)=>{
PhotoService.read(req.params.photoid)
//returns promise - argument passed photos
.then((photo)=>{
console.log(`API: Found images: ${photo}`);
res.status(200);
//set content type header to application/json - set correct mime type
res.send(JSON.stringify(photo));
}).catch((err)=>{
});
});
// /photos POST create
router.post('/', upload.single('image'), async (req, res, next)=>{
var path = "/static/img/" + req.file.filename;
var photo = {
originalname: req.file.originalname,
mimetype: req.file.mimetype,
imageurl: path,
title: req.body.title,
filename: req.file.filename,
description: req.body.description,
size: req.file.size / 1024 | 0
}
//calling on photo service to return json object
try{
const photoSave = await PhotoService.create(photo);
res.status(201);
res.send(JSON.stringify(photoSave));
}catch(err){
console.log(err);
throw new Error("PhotoSaveError", photo);
}
});
// /photos/photoid: PUT - update
router.put('/:photoid', (req, res, next)=>{
console.log(`putting ${req.params.photoid}`);
let putdata = req.body;
PhotoService.update(req.params.photoid, putdata)
console.log()
.then((updatePhoto)=>{
res.status(200);
res.send(JSON.stringify(updatedPhoto));
}).catch((err)=> {
res.status(404);
res.end();
});
});
// /photos/photoid: DELETE - delete
router.delete('/:photoid', (req, res, next)=>{
PhotoService.delete(req.params.photoid)
.then((photo) => {
console.log(`Found images: $(photo)`);
res.status(200);
res.send(JSON.stringify(photo));
}).catch((err)=> {
res.status(404);
res.end();
});;
});
module.exports = router;
photo.js
//photos.js
var express = require('express');
var router = express.Router();
var app = express();
var multer = require('multer');
var photoController = require('../controllers/photoController');
var flash = require('express-flash');
//create upload object- intialize
var upload = multer({
storage: photoController.storage,
fileFilter: photoController.imageFilter
});
//Photo model import is required
var Photo = require('../models/photoModel');
const PhotoService = photoController.PhotoService
//flash messaging
router.use(flash());
//LIST - Get request to search database for our photos
router.get('/', (req, res, next)=>{
//search the DB for the photos
PhotoService.list()
.then((photos)=>{
//call photos view
res.render('photos', {
photos : photos,
flashMsg: req.flash("fileUploadError")
});
})
.catch((err)=>{
if (err) {
res.end("ERROR!");
}
});
});
//FIND - route for getting photo Details with form for editing
router.get('/:photoid', (req, res, next)=>{
console.log("finding "+req.params.photoid);
PhotoService.read({'_id': req.params.photoid})
//return promoise then handle it to render photo
.then((photo)=>{
res.render('updatePhoto', {
photo: photo,
flashMsg: req.flash("photoFindError")
});
}).catch((err)=>{
if (err) console.log(err);
});
});
//DELETE - route for deleting the photos
router.delete('/delete/:photoid', function(req, res){
PhotoService.delete({'_id': req.params.photoid})
.then((photos) => {
res.redirect('/photos');
});
});
//UPDATE - route for posting newly updated details
router.post('/:photoid', (req, res, next)=>{
PhotoService.update({'_id': req.params.photoid})
//return promoise then set photo data details
.then((photo)=>{
var data = {
title: req.body.title,
description: req.body.description
}
//set the data, save the photo details and redirect to photo list
photo.set(data);
photo.save().then(()=>{
res.redirect('/photos');
});
})
.catch((err)=>{
if (err) console.log(err);
});
});
//CREATE - post fields to the server and save them
router.post('/', upload.single('image'), (req, res, next)=>{
var path = "/static/img/" + req.file.filename;
var photo = {
originalname: req.file.originalname,
mimetype: req.file.mimetype,
imageurl: path,
title: req.body.title,
filename: req.file.filename,
description: req.body.description,
size: req.file.size / 1024 | 0
}
//Saving photo to DB
var photo = new Photo(photo);
photo.save()
.then(()=>{
//redirect after save, if succesfull
res.redirect('/photos');
})
//Catch error logs error
.catch((err)=>{
if (err){
console.log(err);
throw new Error("PhotoSaveError", photo);
}
});
});
//function will get called if above gets unhandled error - flash to display image and redirect
router.use(function(err, req, res, next){
console.error(err.stack);
if (err.message == "OnlyImageFilesAllowed"){
req.flash('fileUploadError', "Please select an image file with jpg, png, or gif")
res.redirect('/photos');
//2nd condition error if there was a problem saving
} else if (err.message == "PhotoSaveError"){
req.flash('photoSaveError', "There was a problem saving the photo")
res.redirect('/photos');
} else{
next(err);
}
});
//export the module
module.exports = router;
api.js
// wrap in IIFE to control scope
(function(){
const baseURL = 'http://localhost:8080';
function testAPIs(){
// test list first
var testId = '';
var testJSON = {};
// list
callAPI('GET', '/api/photos', null, null)
.then((list)=>{
console.log('\n\n***************************\nlist results:');
console.log(list);
testId = list[0]._id;
// create
let input = document.querySelector('input[type="file"]')
let data = new FormData()
data.append('image', input.files[0]);
data.append('title', 'My API Test Title');
data.append('description','This is an AJAX API test');
callAPI('POST', '/api/photos', null, data)
.then((photo)=>{
photoId = photo._id;
savedPhoto = photo; // keep a handle to the created photo object
console.log('\n\n***************************\ncreate results:');
console.log(photo);
// find
callAPI('GET','/api/photos/'+photoId, null, null)
.then((photo)=>{
console.log('\n\n***************************\nfind results:');
console.log(photo);
// update
testJSON.description += ' appended by the AJAX API ';
callAPI('PUT','/api/photos/'+photoId, null, savedPhoto)
.then((photo)=>{
console.log('\n\n***************************\nupdate results:');
console.log(photo);
//delete
callAPI('DELETE', '/api/photos/'+photoId, null, null)
.then((result)=>{
console.log('\n\n***************************\ndelete result:');
console.log(result);
})
});
});
});
})
.catch((err)=>{
console.error(err);
});
}
async function callAPI(method, uri, params, body){
jsonMimeType = {
'Content-type':'application/json'
}
try{
/* Set up our fetch.
* 'body' to be included only when method is POST
* If 'PUT', we need to be sure the mimetype is set to json
* (so bodyparser.json() will deal with it) and the body
* will need to be stringified.
* '...' syntax is the ES6 spread operator.
* It assigns new properties to an object, and in this case
* lets us use a conditional to create, or not create, a property
* on the object. (an empty 'body' property will cause an error
* on a GET request!)
*/
var response = await fetch(baseURL + uri, {
method: method, // GET, POST, PUT, DELETE, etc.
...(method=='POST' ? {body: body} : {}),
...(method=='PUT' ? {headers: jsonMimeType, body:JSON.stringify(body)} : {})
});
return response.json(); // parses response to JSON
}catch(err){
console.error(err);
return "{'status':'error'}";
}
}
// Calls our test function when we click the button
// afer validating that there's a file selected.
document.querySelector('#testme').addEventListener("click", ()=>{
let input = document.querySelector('input[type="file"]')
if (input.value){
testAPIs();
}else{
alert("please select an image file first");
}
});
})();
答案 0 :(得分：0)
这是一个更新PUT处理程序，它应该停止抛出＆＃34; undefined。然后...＆＃34;，注意updatePhoto也需要重命名为updatedPhoto。< / p>
router.put('/:photoid', (req, res, next) => {
console.log(`putting ${req.params.photoid}`);
let putdata = req.body;
PhotoService.update(req.params.photoid, putdata).then((updatedPhoto) => {
res.status(200);
res.send(JSON.stringify(updatedPhoto));
}).catch((err) => {
res.status(404);
res.end();
});
});
如果您使用的是节点8+，则可以使用async / await。它简化了代码并使问题更容易看到：
router.put('/:photoid', async (req, res, next) => {
try {
console.log(`putting ${req.params.photoid}`);
let putdata = req.body;
const updatedPhoto = await PhotoService.update(req.params.photoid, putdata);
res.status(200);
res.send(JSON.stringify(updatedPhoto));
} catch (e) {
res.status(404);
res.end();
}
});