express.js 4 GET请求中的JSON解析问题（从数据表请求数据） [英] express.js 4 JSON parsing problems from GET request (request data from datatables)
问题描述
我在解析序列化的JSON Ajax Get请求（使用jQuery $ .ajax）发送到我的express.js 4服务器时遇到问题。以JSON请求发送的数据是由数据表生成的。
这是我如何在客户端开始
< pre class =lang-js prettyprint-override>
$（document）.ready（function（）{
$（'＃example'）。dataTable（{
bServerSide ：true，
fnServerData：function（sSource，aoData，fnCallback）{
$ .ajax（{
dataType：'json'，
contentType：'application / json'，
type：GET，
url：http：// localhost：3000 / ajax / phenotypes / withOrg / like / datatables /，
数据：aoData，
success：fnCallback，
error：function（）{
alert（'have some problem'）;
}
} ）;
}
}）;
}）;
当我在浏览器中加载此代码时，数据表会生成以下GET请求URL（到服务器）：
GET
/ ajax /表型/ withOrg / like / datatables /？draw = 1& columns =％5Bobject + 5D％2C％5B对象+对象％5D％2C％5B对象+对象％5D％2C％5B对象+对象％5D％2C％5B对象+对象％5D％2C％5B对象+对象％5D&顺序=％5B对象+对象％5D& ; start = 0& length = 10& search =％5Bobject + Object％5D
或解码形式（从firebug输出） / p>
columns [object Object]，[object Object]，[object Object]，[object Object]，[object Object] object object]
draw 1
length 10
order [object Object]
search [object Object]
start 0
所以我发送之前序列化数据
$（document）.ready（function（）{
$（'＃example '）.dataTable（{
bServerSide：true，
fnServerData：function（sSource，aoData，fnCallback）{
var myData = JSON.stringify（aoData）;
$ .ajax（{
dataType：'json'，
contentType：'application / json'，
type：GET，
url：http：// localhost：3000 / ajax /表型/ withOrg / like / datatables /，
data：myData，
success：fnCallback，
：function（）{
alert（'have some problem'）;
}
}）;
}
}）;
}）;
这里是从数据表生成的GET参数：
GET
/ ajax /表型/ withOrg / like / datatables /？[{％22name％22：％22draw％22，％22value％22：1}，{％22name ％22：％22列％22，％22value％22：[{％22data％22：0，％22name％22：％22％22，％22searchable％22：true，％22orderable％22：true，％22search％22 ：{％22value％22：％22％22，％22regex％22：false}}，{％22data％22：1，％22name％22：％22％22，％22searchable％22：true，％22orderable％22 ：true，％22search％22：{％22value％22：％22％22，％22regex％22：false}}，{％22data％22：2，％22name％22：％22％22，％22searchable％22 ：true，％22orderable％22：true，％22search％22：{％22value％22：％22％22，％22regex％22：false}}，{％22data％22：3，％22name％22：％22 ％22searchable％22：true，％22orderable％22：true，％22search％22：{％22value％22：％22％22，％22regex％22：false}}，{％22data％22： ％22name％22：％22％22，％22searchable％22：true，％22orderable％22：true，％22search％22：{％22value％22：％22％22，％22regex％22：false}}，{ ％22数据％22：5，％22name％22：％22％22，％22searchable％22：true，％22orderable％22：true，％22search％22：{％22value％22：％2 2％22，％22regex％22：false}}]}，{％22name％22：％22order％22，％22value％22：[{％22column％22：0，％22dir％22：％22asc％22} ]，{％22name％22：％22start％22，％22value％22：0}，{％22name％22：％22length％22，％22value％22：10}，{％22name％22：％22search％ 22，％22value％22：{％22value％22：％22％22，％22regex％22：false}}]
HTTP / 1.1
解码形式（从firebug输出并使用在线工具进行美化 - 用jslint进行检查，似乎正确！）
name：draw，
value：1
}，
{
name列，
value：[
{
data：0，
name：，
可搜索：true，
orderable：true，
search：{
value：，
regex：false
}
}，
{
data：1，
name：，
可搜索：true，
可订购：true，
search：{
value：，
regex：false
}
}，
{
data：2 ，
name：，
可搜索：true，
可订购：true，
search：{
value ，
regex：false
}
}，
{
data：3，
name：，
searchable：true，
orderable：true，
search：{
value：，
regex：false
}，
{
data：4，
name：，
可搜索：true，
：true，
search：{
value：，
regex：false
}
}，
{
data：5，
name：，
可搜索：true，
可订购：true，
search：{
value：，
regex：false
}
}
]
}，
{
name：order，
value ：[
{
column：0，
dir：asc
}
]
}，
{
name：start，
value：0
}，
{
name：length，
value ：10
}，
{
name：search，
value：{
value：，
regex：false
}
}
]
问题是现在这个字符串的URL不能在express 4服务器端解析
我使用express4 req.query和url.parse方法： http://expressjs.com/api.html#req.query
和t母鸡尝试用JSON.parse（）方法解析收到的json字符串
...
var url = require（'url'）;
...
router.get（'/ withOrg / like / datatables /'，function（req，res）{
console.log（'通过req获取json字符串.query'）;
console.log（req.query）;
console.log（'使用JSON.parse输出解析的json对象）;
console.log（JSON.parse（ req.query））;
//另一个尝试
console.log（'为堆栈溢出测试2'）;
console.log（url.parse（req.url ，true）.query）;
console.log（'使用JSON.parse输出解析的json对象）;
console.log（url.parse（req.url，true）.query）;
}）
两个json字符串输出结果都是无效的json，你可以在这里看到，无法解析JSON.parse：
通过req.query获取json字符串pre>
{
'{data：0，name：，可搜索：true，可靠的：true，可搜索：true，可订购：true ，搜索：{va lue：，regex：false}}，{data：2，name：，可搜索：true，orderable：true，search：{value ，regex：false}}，{data：3，name：，可搜索：true，orderedable：true，search：{value：，regex ：false}}，{data：4，name：，可搜索：true，orderable：true，search：{value：，regex }，{data：5，name：，searchable：true，orderable：true，search：{value：，regex：false} b $ b {'{column：0，dir：asc}'：''}}
使用JSON.parse输出解析的json对象
通过req.query获取json字符串
{
'{data：0，name：，可搜索：true，orderedable搜索：{value：，regex：false}}，{data：1，name：，可搜索：true，orderable value：，regex：false}}，{data：2，name：，可搜索：true，orderable：true，search：{value ，regex：false}}，{data：3，name：，可搜索：true，orderedable：true，search：{value regex：false}}，{data：4，name：，可搜索：true，orderedable：true，search：{value：，regex false}}，{data：5，name：，可搜索：true，orderable：true，search：{value：，regex ：
{'{column：0，dir：asc}'：''}}
< p $ p>输出解析json对象使用JSON.parse
当我尝试解析json字符串我从JSON.parse中获取错误
SyntaxError：意外的令牌o
在Object.parse （native）
在module.exports（/Users/xxx/yyy/routes/phenotypesAJAX.js:16:19）
在Layer.handle [as handle_request]（/ Users / xxx / yyy / node_modules /express/lib/router/layer.js:82:5）
在下一个（/Users/xxx/yyy/node_modules/express/lib/router/route.js:100:13）
这是一个在快递4中的错误？
我看不到问题在哪里。在客户端，序列化的datatable GET请求似乎有效（使用JSLint检查）。在express4服务器端，我找不到任何其他方法来解析GET请求。
非常感谢你的帮助，
Oliver
我在快速github bugtracker上发布了这个问题的答案。
经验教训：
我正在想复杂，express.js请求方法不是特别为特定的请求格式写的！他们只是使用发送给他们的数据格式，而无需修改！
我先使用的方法：
req.query
[。 。]只适用于标准查询字符串，这是key = value对，
，您给的URL不是。[..]
解决我的问题的正确方法是：
url.parse（req.url）.query
返回不必手动解码的URL的完整参数字符串：
obj = JSON.parse（decodeURIComponent（query））
这是完整的解释：
https：// github。 com / strongloop / express / issues / 2460
I am having problems parsing a serialized JSON Ajax Get request (using jQuery $.ajax) send to my express.js 4 server. The data send as a JSON request is generated by datatables.
Here is how I started on the client-side
$(document).ready(function() {
$('#example').dataTable( {
"bServerSide": true,
"fnServerData": function (sSource, aoData, fnCallback) {
$.ajax({
"dataType": 'json',
contentType: 'application/json',
"type": "GET",
"url": "http://localhost:3000/ajax/phenotypes/withOrg/like/datatables/",
"data": aoData,
"success": fnCallback,
"error": function () {
alert('have some problem');
}
});
}
} );
} );
when I load this code in the brower datatables generates the following GET request URL (to the server):
GET /ajax/phenotypes/withOrg/like/datatables/?draw=1&columns=%5Bobject+Object%5D%2C%5Bobject+Object%5D%2C%5Bobject+Object%5D%2C%5Bobject+Object%5D%2C%5Bobject+Object%5D%2C%5Bobject+Object%5D&order=%5Bobject+Object%5D&start=0&length=10&search=%5Bobject+Object%5D
or in decoded form (output from firebug)
columns [object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
draw 1
length 10
order [object Object]
search [object Object]
start 0
so I serialized the data before sending
$(document).ready(function() {
$('#example').dataTable( {
"bServerSide": true,
"fnServerData": function (sSource, aoData, fnCallback) {
var myData = JSON.stringify(aoData);
$.ajax({
"dataType": 'json',
contentType: 'application/json',
"type": "GET",
"url": "http://localhost:3000/ajax/phenotypes/withOrg/like/datatables/",
"data": myData,
"success": fnCallback,
"error": function () {
alert('have some problem');
}
});
}
} );
} );
here is the generated GET parameters from datatables:
GET /ajax/phenotypes/withOrg/like/datatables/?[{%22name%22:%22draw%22,%22value%22:1},{%22name%22:%22columns%22,%22value%22:[{%22data%22:0,%22name%22:%22%22,%22searchable%22:true,%22orderable%22:true,%22search%22:{%22value%22:%22%22,%22regex%22:false}},{%22data%22:1,%22name%22:%22%22,%22searchable%22:true,%22orderable%22:true,%22search%22:{%22value%22:%22%22,%22regex%22:false}},{%22data%22:2,%22name%22:%22%22,%22searchable%22:true,%22orderable%22:true,%22search%22:{%22value%22:%22%22,%22regex%22:false}},{%22data%22:3,%22name%22:%22%22,%22searchable%22:true,%22orderable%22:true,%22search%22:{%22value%22:%22%22,%22regex%22:false}},{%22data%22:4,%22name%22:%22%22,%22searchable%22:true,%22orderable%22:true,%22search%22:{%22value%22:%22%22,%22regex%22:false}},{%22data%22:5,%22name%22:%22%22,%22searchable%22:true,%22orderable%22:true,%22search%22:{%22value%22:%22%22,%22regex%22:false}}]},{%22name%22:%22order%22,%22value%22:[{%22column%22:0,%22dir%22:%22asc%22}]},{%22name%22:%22start%22,%22value%22:0},{%22name%22:%22length%22,%22value%22:10},{%22name%22:%22search%22,%22value%22:{%22value%22:%22%22,%22regex%22:false}}] HTTP/1.1
in decoded form (output from firebug and beautified using an online tool- checked with jslint, seems correct!)
[
{
"name":"draw",
"value":1
},
{
"name":"columns",
"value":[
{
"data":0,
"name":"",
"searchable":true,
"orderable":true,
"search":{
"value":"",
"regex":false
}
},
{
"data":1,
"name":"",
"searchable":true,
"orderable":true,
"search":{
"value":"",
"regex":false
}
},
{
"data":2,
"name":"",
"searchable":true,
"orderable":true,
"search":{
"value":"",
"regex":false
}
},
{
"data":3,
"name":"",
"searchable":true,
"orderable":true,
"search":{
"value":"",
"regex":false
}
},
{
"data":4,
"name":"",
"searchable":true,
"orderable":true,
"search":{
"value":"",
"regex":false
}
},
{
"data":5,
"name":"",
"searchable":true,
"orderable":true,
"search":{
"value":"",
"regex":false
}
}
]
},
{
"name":"order",
"value":[
{
"column":0,
"dir":"asc"
}
]
},
{
"name":"start",
"value":0
},
{
"name":"length",
"value":10
},
{
"name":"search",
"value":{
"value":"",
"regex":false
}
}
]
the problem is now that this stringified URL can not be parsed on the express 4 server side I use express4 req.query and url.parse method for this : http://expressjs.com/api.html#req.query and then try to parse the received json string with the JSON.parse() method
...
var url = require('url');
...
router.get('/withOrg/like/datatables/', function (req, res) {
console.log('getting json string via req.query');
console.log(req.query);
console.log('output parsed json object using JSON.parse');
console.log(JSON.parse(req.query));
//another try
console.log('for stack overflows test 2');
console.log(url.parse(req.url, true).query);
console.log('output parsed json object using JSON.parse');
console.log(url.parse(req.url, true).query);
})
both json string output results are invalid json as you can see here and unable to parse with JSON.parse:
getting json string via req.query
{ '{"data":0,"name":"","searchable":true,"orderable":true,"search":{"value":"","regex":false}},{"data":1,"name":"","searchable":true,"orderable":true,"search":{"value":"","regex":false}},{"data":2,"name":"","searchable":true,"orderable":true,"search":{"value":"","regex":false}},{"data":3,"name":"","searchable":true,"orderable":true,"search":{"value":"","regex":false}},{"data":4,"name":"","searchable":true,"orderable":true,"search":{"value":"","regex":false}},{"data":5,"name":"","searchable":true,"orderable":true,"search":{"value":"","regex":false}}': { '{"column":0,"dir":"asc"}': '' } }
output parsed json object using JSON.parse
getting json string via req.query
{ '{"data":0,"name":"","searchable":true,"orderable":true,"search":{"value":"","regex":false}},{"data":1,"name":"","searchable":true,"orderable":true,"search":{"value":"","regex":false}},{"data":2,"name":"","searchable":true,"orderable":true,"search":{"value":"","regex":false}},{"data":3,"name":"","searchable":true,"orderable":true,"search":{"value":"","regex":false}},{"data":4,"name":"","searchable":true,"orderable":true,"search":{"value":"","regex":false}},{"data":5,"name":"","searchable":true,"orderable":true,"search":{"value":"","regex":false}}': { '{"column":0,"dir":"asc"}': '' } }
output parsed json object using JSON.parse
when I try to parse the json string I get the error from JSON.parse
SyntaxError: Unexpected token o
at Object.parse (native)
at module.exports (/Users/xxx/yyy/routes/phenotypesAJAX.js:16:19)
at Layer.handle [as handle_request] (/Users/xxx/yyy/node_modules/express/lib/router/layer.js:82:5)
at next (/Users/xxx/yyy/node_modules/express/lib/router/route.js:100:13)
Is this a bug in express 4? I cannot see where the problem is. On the client-side the serialized datatable GET request seems valid (checked with JSLint). On the express4 server side I cannot find any other way to parse the GET request in a different way.
Thank you so much for your help, Oliver
I have got the answer from posting this problem at the express github bugtracker. Lesson learned: I was thinking to complicated, express.js request methods are not written especially for a specific request format! They just use the data format which was send to them without modification!
The method I used first:
req.query
[..] only works with standard query strings, which are key=value pairs, which the URL you gave was not.[..]
The correct method to solve my problem is:
url.parse(req.url).query
returns the complete parameter string of an URL which than has to be decoded manually:
obj = JSON.parse(decodeURIComponent(query))
Here is the full explanation: https://github.com/strongloop/express/issues/2460
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