当我通过测试位或通过POSTMAN向API网关上的API发送请求时，请求的发送和接收都很好，我可以得到预期的响应体，但是，当我通过下面的代码发出API请求时，我得到了502错误。
CORS策略没有问题，因为我没有收到任何错误，这是我的请求代码和随后的错误。
POST REQUEST CODE
fetch('https://4diopo9a77.execute-api.eu-west-2.amazonaws.com/DSA_API/imagedata', {
method: 'POST',
body :"{'A':'A'}"
}).then(function(data) {
console.log(data)
})
控制台输出
POST `API_NAME` 502
Response {type: 'cors', url: '*API_NAME*', redirected: false, status: 502, ok: false, …}
错误1堆栈跟踪
POSTRequest @ Home.js:15
getFileData @ Home.js:49
callCallback @ react-dom.development.js:3945
invokeGuardedCallbackDev @ react-dom.development.js:3994
invokeGuardedCallback @ react-dom.development.js:4056
invokeGuardedCallbackAndCatchFirstError @ react-dom.development.js:4070
executeDispatch @ react-dom.development.js:8243
processDispatchQueueItemsInOrder @ react-dom.development.js:8275
processDispatchQueue @ react-dom.development.js:8288
dispatchEventsForPlugins @ react-dom.development.js:8299
(anonymous) @ react-dom.development.js:8508
batchedEventUpdates$1 @ react-dom.development.js:22396
batchedEventUpdates @ react-dom.development.js:3745
dispatchEventForPluginEventSystem @ react-dom.development.js:8507
attemptToDispatchEvent @ react-dom.development.js:6005
dispatchEvent @ react-dom.development.js:5924
unstable_runWithPriority @ scheduler.development.js:468
runWithPriority$1 @ react-dom.development.js:11276
discreteUpdates$1 @ react-dom.development.js:22413
discreteUpdates @ react-dom.development.js:3756
dispatchDiscreteEvent @ react-dom.development.js:5889
错误2详细信息
body: ReadableStream
bodyUsed: false
headers: Headers {}
ok: false
redirected: false
status: 502
statusText: ""
type: "cors"
url: "*API_NAME*"
[[Prototype]]: Response
这是POSTMAN请求信息的图片
需要将Cors标题添加到响应中，浏览器阻止了响应，因为它没有返回标题，添加了这个并起到了作用：
"Access-Control-Allow-Origin": '*'
所以我在lambda中的返回看起来是这样的：
return {
"statusCode": 200,
"body": json.dumps(data),
"headers": {
'Content-Type': 'application/JSON',
"Access-Control-Allow-Origin": '*'
},
}