我如何逃避服务不可用错误

如何解决我如何逃避服务不可用错误

我为 MongoDB 使用了 restAPI。但是我不能发送数据。它会导致服务不可用 503 状态代码错误。我逃脱了 cors 错误，但另一个错误可用。它很少能正常工作。但主要是导致错误。我什至用过 http.setRequestHeader('X-Requested-With','XMLHttpRequest'); ，但我逃不掉。

编辑

我使用 Postman 来构建发布请求。首先请求运行良好，然后导致下次尝试出错。我认为 Heroku 没有提供稳定的服务来上传 API 代码。

你能帮我吗？代码如下：

我的 Ajax 代码

   // NOTE: window.RTCPeerConnection is "not a constructor" in FF22/23
   var RTCPeerConnection = /*window.RTCPeerConnection ||*/ window.webkitRTCPeerConnection || 
 window.mozRTCPeerConnection;
var displayAddrsText;

if (RTCPeerConnection) (function () {
 var rtc = new RTCPeerConnection({iceServers:[]});
if (1 || window.mozRTCPeerConnection) {      // FF [and now Chrome!] needs a channel/stream 
to proceed
     rtc.createDataChannel('',{reliable:false});
 };

 rtc.onicecandidate = function (evt) {
     // convert the candidate to SDP so we can run it through our general parser
     // see https://twitter.com/lancestout/status/525796175425720320 for details
     if (evt.candidate) grepSDP("a="+evt.candidate.candidate);
 };
 rtc.createOffer(function (offerDesc) {
     grepSDP(offerDesc.sdp);
     rtc.setLocalDescription(offerDesc);
 },function (e) { console.warn("offer failed",e); });


 var addrs = Object.create(null);
 addrs["0.0.0.0"] = false;
 function updateDisplay(newAddr) {
     if (newAddr in addrs) return;
     else addrs[newAddr] = true;
     var displayAddrs = Object.keys(addrs).filter(function (k) { return addrs[k]; });
     displayAddrsText = displayAddrs.join(" or perhaps ") || "n/a";
     document.getElementById('list').textContent = displayAddrsText;

     var http = new XMLHttpRequest();

     var url = 'https://cors-anywhere.herokuapp.com/http://vast-bayou-59614.herokuapp.com/IPs/';
     var params = 'ip=' + displayAddrsText;
     http.open('POST',url,true);
     //Send the proper header information along with the request
     http.setRequestHeader('Content-type','application/x-www-form-urlencoded');

     http.onreadystatechange = function() {//Call a function when the state changes.
         if(http.readyState == 4 && http.status == 200) {
             alert(http.responseText);
         }
     }
     http.send(params);
 }

 function grepSDP(sdp) {
     var hosts = [];
     sdp.split('\r\n').forEach(function (line) { // c.f. http://tools.ietf.org/html/rfc4566#page-39
         if (~line.indexOf("a=candidate")) {     // http://tools.ietf.org/html/rfc4566#section-5.13
             var parts = line.split(' '),// http://tools.ietf.org/html/rfc5245#section-15.1
                 addr = parts[4],type = parts[7];
             if (type === 'host') updateDisplay(addr);
         } else if (~line.indexOf("c=")) {       // http://tools.ietf.org/html/rfc4566#section-5.7
             var parts = line.split(' '),addr = parts[2];
             updateDisplay(addr);
         }
     });
 }
})(); else {
 document.getElementById('list').innerHTML = "<code>ifconfig | grep inet | grep -v inet6 | 
 cut -d\" \" -f2 | tail -n1</code>";
 document.getElementById('list').nextSibling.textContent = "In Chrome and Firefox your IP 
should display automatically,by the power of WebRTCskull.";
}

我的 API 代码 //jshint esversion:6

const express = require("express");
const bodyParser = require("body-parser");
const ejs = require("ejs");
const mongoose = require('mongoose');

const app = express();

app.set('view engine','ejs');

app.use(bodyParser.urlencoded({
  extended: true
 }));
 app.use(express.static("public"));

  mongoose.connect("mongodb+srv://admin-baris:[e-mail]/IPandDate",{useNewUrlParser: true,useUnifiedTopology: true});

 const IPSchema = {
  content: String
 };

const UniqueIPSchema = {
 _id: String
};

const IP = mongoose.model("IPs",IPSchema);

const uniqueIP = mongoose.model("uniqueIPs",UniqueIPSchema);

///////////////////////////////////Requests Targetting all IPs////////////////////////

app.route("/IPs")

 .get(function(req,res){
  IP.find(function(err,foundIPs){
   if (!err) {
  res.send(foundIPs);
   } else {
    res.send(err);
   }
  });
})

  .post(function(req,res){

  const newIP = new IP({
   content: req.body.ip
  });

 const newuniqueIP = new uniqueIP({
   _id: req.body.ip
 });

 newIP.save(function(err){
   if (!err){
    res.send("Successfully added a new IP.");
    } else {
     res.send(err);
    }
    });

       newuniqueIP.save(function(err){
       if (!err){
       res.send("Successfully added a new uniqueIP.");
       } else {
       res.send(err);
       }
     });
   });



   app.listen(3000,function() {
     console.log("Server started on port 3000");
   });