我正在使用Node JS应用程序测试facebook leadgen api。 使用Facebook测试工具，我收到了Facebook的回复。当我尝试JSON.stringify（）时，我将循环结构转换为JSON错误。如何获取字段leadgen的值。
来自facebook的测试数据：
{
"field": "leadgen",
"value": {
"ad_id": "444444444",
"form_id": "444444444444",
"leadgen_id": "444444444444",
"created_time": 1497678903,
"page_id": "444444444444",
"adgroup_id": "44444444444"
}
}
我尝试使用日志打印响应。但回应看起来像这样。我无法理解如何解析它。
ServerResponse {
domain: null,
_events: { finish: [Function: resOnFinish] },
_eventsCount: 1,
_maxListeners: undefined,
output: [],
outputEncodings: [],
outputCallbacks: [],
outputSize: 0,
writable: true,
_last: false,
upgrading: false,
chunkedEncoding: false,
shouldKeepAlive: false,
useChunkedEncodingByDefault: false,
sendDate: true,
_removedHeader: {},
_contentLength: null,
_hasBody: true,
_trailer: '',
finished: false,
_headerSent: false,
socket:
Socket {
connecting: false,
_hadError: false,
_handle:
TCP {
bytesRead: 611,
_externalStream: {},
fd: 14,
reading: true,
owner: [Circular],
onread: [Function: onread],
onconnection: null,
writeQueueSize: 0,
_consumed: true },
_parent: null,
_host: null,
_readableState:
ReadableState {
objectMode: false,
highWaterMark: 16384,
buffer: [Object],
length: 0,
pipes: null,
pipesCount: 0,
flowing: true,
ended: false,
endEmitted: false,
reading: true,
sync: false,
needReadable: true,
emittedReadable: false,
readableListening: false,
resumeScheduled: false,
defaultEncoding: 'utf8',
ranOut: false,
awaitDrain: 0,
readingMore: false,
decoder: null,
encoding: null },
readable: true,
domain: null,
_events:
{ end: [Object],
finish: [Function: onSocketFinish],
_socketEnd: [Function: onSocketEnd],
drain: [Object],
timeout: [Function],
error: [Function: socketOnError],
close: [Object],
data: [Function: socketOnData],
resume: [Function: onSocketResume],
pause: [Function: onSocketPause] },
_eventsCount: 10,
_maxListeners: undefined,
_writableState:
WritableState {
objectMode: false,
highWaterMark: 16384,
needDrain: false,
ending: false,
ended: false,
finished: false,
decodeStrings: false,
defaultEncoding: 'utf8',
length: 0,
writing: false,
corked: 0,
sync: true,
bufferProcessing: false,
onwrite: [Function],
writecb: null,
writelen: 0,
bufferedRequest: null,
lastBufferedRequest: null,
pendingcb: 0,
prefinished: false,
errorEmitted: false,
bufferedRequestCount: 0,
corkedRequestsFree: [Object] },
writable: true,
allowHalfOpen: true,
destroyed: false,
_bytesDispatched: 0,
_sockname: null,
_pendingData: null,
_pendingEncoding: '',
server:
Server {
domain: null,
_events: [Object],
_eventsCount: 2,
_maxListeners: undefined,
_connections: 1,
_handle: [Object],
_usingSlaves: false,
_slaves: [],
_unref: false,
allowHalfOpen: true,
pauseOnConnect: false,
httpAllowHalfOpen: false,
timeout: 120000,
_pendingResponseData: 0,
_connectionKey: '6::::5050' },
_server:
Server {
domain: null,
_events: [Object],
_eventsCount: 2,
_maxListeners: undefined,
_connections: 1,
_handle: [Object],
_usingSlaves: false,
_slaves: [],
_unref: false,
allowHalfOpen: true,
pauseOnConnect: false,
httpAllowHalfOpen: false,
timeout: 120000,
_pendingResponseData: 0,
_connectionKey: '6::::5050' },
_idleTimeout: 120000,
_idleNext:
TimersList {
_idleNext: [Circular],
_idlePrev: [Circular],
_timer: [Object],
_unrefed: true,
msecs: 120000,
nextTick: false },
_idlePrev:
TimersList {
_idleNext: [Circular],
_idlePrev: [Circular],
_timer: [Object],
_unrefed: true,
msecs: 120000,
nextTick: false },
_idleStart: 14449,
parser:
HTTPParser {
'0': [Function: parserOnHeaders],
'1': [Function: parserOnHeadersComplete],
'2': [Function: parserOnBody],
'3': [Function: parserOnMessageComplete],
'4': [Function: onParserExecute],
_headers: [],
_url: '',
_consumed: true,
socket: [Circular],
incoming: [Object],
outgoing: null,
maxHeaderPairs: 2000,
onIncoming: [Function: parserOnIncoming] },
on: [Function: socketOnWrap],
_paused: false,
read: [Function],
_consuming: true,
_httpMessage: [Circular] },
connection:
Socket {
connecting: false,
_hadError: false,
_handle:
TCP {
bytesRead: 611,
_externalStream: {},
fd: 14,
reading: true,
owner: [Circular],
onread: [Function: onread],
onconnection: null,
writeQueueSize: 0,
_consumed: true },
_parent: null,
_host: null,
_readableState:
ReadableState {
objectMode: false,
highWaterMark: 16384,
buffer: [Object],
length: 0,
pipes: null,
pipesCount: 0,
flowing: true,
ended: false,
endEmitted: false,
reading: true,
sync: false,
needReadable: true,
emittedReadable: false,
readableListening: false,
resumeScheduled: false,
defaultEncoding: 'utf8',
ranOut: false,
awaitDrain: 0,
readingMore: false,
decoder: null,
encoding: null },
readable: true,
domain: null,
_events:
{ end: [Object],
finish: [Function: onSocketFinish],
_socketEnd: [Function: onSocketEnd],
drain: [Object],
timeout: [Function],
error: [Function: socketOnError],
close: [Object],
data: [Function: socketOnData],
resume: [Function: onSocketResume],
pause: [Function: onSocketPause] },
_eventsCount: 10,
_maxListeners: undefined,
_writableState:
WritableState {
objectMode: false,
highWaterMark: 16384,
needDrain: false,
ending: false,
ended: false,
finished: false,
decodeStrings: false,
defaultEncoding: 'utf8',
length: 0,
writing: false,
corked: 0,
sync: true,
bufferProcessing: false,
onwrite: [Function],
writecb: null,
writelen: 0,
bufferedRequest: null,
lastBufferedRequest: null,
pendingcb: 0,
prefinished: false,
errorEmitted: false,
bufferedRequestCount: 0,
corkedRequestsFree: [Object] },
writable: true,
allowHalfOpen: true,
destroyed: false,
_bytesDispatched: 0,
_sockname: null,
_pendingData: null,
_pendingEncoding: '',
server:
Server {
domain: null,
_events: [Object],
_eventsCount: 2,
_maxListeners: undefined,
_connections: 1,
_handle: [Object],
_usingSlaves: false,
_slaves: [],
_unref: false,
allowHalfOpen: true,
pauseOnConnect: false,
httpAllowHalfOpen: false,
timeout: 120000,
_pendingResponseData: 0,
_connectionKey: '6::::5050' },
_server:
Server {
domain: null,
_events: [Object],
_eventsCount: 2,
_maxListeners: undefined,
_connections: 1,
_handle: [Object],
_usingSlaves: false,
_slaves: [],
_unref: false,
allowHalfOpen: true,
pauseOnConnect: false,
httpAllowHalfOpen: false,
timeout: 120000,
_pendingResponseData: 0,
_connectionKey: '6::::5050' },
_idleTimeout: 120000,
_idleNext:
TimersList {
_idleNext: [Circular],
_idlePrev: [Circular],
_timer: [Object],
_unrefed: true,
msecs: 120000,
nextTick: false },
_idlePrev:
TimersList {
_idleNext: [Circular],
_idlePrev: [Circular],
_timer: [Object],
_unrefed: true,
msecs: 120000,
nextTick: false },
_idleStart: 14449,
parser:
HTTPParser {
'0': [Function: parserOnHeaders],
'1': [Function: parserOnHeadersComplete],
'2': [Function: parserOnBody],
'3': [Function: parserOnMessageComplete],
'4': [......
答案 0 :(得分：1)
最后经过多次迭代后，下面的代码解决了我的问题：
app.post('url', function(req, res) {
const customStringify = function (res) {
let cache = [];
return JSON.stringify(res, function (key, value) {
if (typeof value === 'object' && value !== null) {
if (cache.indexOf(value) !== -1) {
// Circular reference found, discard key
return;
}
// Store value in our collection
cache.push(value);
}
return value;
});
};
var jsonObj = customStringify(res);
var mainObj = JSON.parse(jsonObj);
var leadObj = mainObj.socket.parser.incoming.body.entry[0].changes[0].value;
console.log(leadObj);
});
答案 1 :(得分：0)
您可以使用此自定义stringify函数，该函数可以处理循环依赖项。这是标准的，我从别人那里偷了它。
const customStringify = function (v) {
let cache = [];
return JSON.stringify(v, function (key, value) {
if (typeof value === 'object' && value !== null) {
if (cache.indexOf(value) !== -1) {
// Circular reference found, discard key
return;
}
// Store value in our collection
cache.push(value);
}
return value;
});
};
虽然如果您正在尝试解析响应，但您可能希望调用JSON.parse而不是JSON.stringify。