Develop Reference

Axios response get 200 code status, but sometimes data is empty

I'm using a Asp.net Core 2.2 Web API and ReactJS Axios, but sometimes (about 1 in 100 times) the response status is 200 but the data is an empty string.
The server side Controller code is:
[Route("api/[controller]")]
[ApiController]
public class SomeApiController : ControllerBase
{
[HttpPost("GetData")]
public IActionResult GetData([FromBody] int id_search)
{
// *Here I get a list data from back using the id_search*
string json = JsonConvert.SerializeObject(List_data, Formatting.Indented));
// *Here I write the json string in a text file, for debbug the data to send*
return Ok(json);
}
}
So far everything is fine, the json string i wrote in the text file have the data like this:
[
{
"cod_db": 1,
"nom_db": "Nom1"
},
{
"cod_db": 2,
"nom_db": "Nom2"
}
]
The Axios client javascript code is (I'm using axios 0.19.2):
import axios from 'axios';
const clienteAxios = axios.create({
baseURL: 'https://localhost:44364/api/'
}):
export default clienteAxios;
The client side axios method is:
const getData = () => {
const config = {
headers: {
'Content-Type': 'application/json',
// * The next headers I wrote because i think the problem could be CORS too, but I dont know if are necessary *
'Access-Control-Allow-Origin': '*',
'Access-Control-Allow-Credentials': true ,
'Cache-Control': 'no-cache',
'Access-Control-Allow-Headers': 'Content-type, Accept'
}
}
var id_search = 1;
clienteAxios.post('SomeApi/GetData', id_search, config)
.then(d=>{
console.log(d);
})
.catch(d=>{
console.log("error");
console.log(d);
})
}
And most of the time the response have data, but sometimes (it is difficult to happen), the response data is an empty string, even though the server side effectively sent data (I know because the text file records the data to send) and the .then method was execute with code status 200.
I don't know why this is happening, but I suspect that it could be because of CORS. I have this cors configurations in the Startup.cs archive:
public void ConfigureServices(IServiceCollection services)
{
services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_2);
//CORS Activación
services.AddCors(
options => options.AddPolicy("EnableCORS",
builder =>
{
builder
.AllowAnyOrigin()
.AllowAnyMethod()
.AllowAnyHeader()
.AllowCredentials()
.Build();
})
);
}
public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
if (env.IsDevelopment())
{
app.UseDeveloperExceptionPage();
}
else
{
// The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
app.UseHsts();
}
//Enable CORS policy "AllowCors"
app.UseCors("EnableCORS");
app.UseHttpsRedirection();
app.UseMvc();
}
Is there something I am doing wrong, or does anyone know why this is happening?
Edit: After a lot of attempts, I finally managed to recreate the error (remember that it is difficult to happen). The Chrome browser developer tools
Console tab shows nothing and the Network tab shows:
Headers:
General:
Request URL: https://localhost:44364/api/Login/GetDataBases
Request Method: POST
Status Code: 200
Remote Address: [::1]:44364
Referrer Policy: no-referrer-when-downgrade
Response Headers:
access-control-allow-credentials: true
access-control-allow-origin: *
content-length: 0
content-type: text/plain; charset=utf-8
date: Fri, 04 Sep 2020 10:16:46 GMT
server: Microsoft-IIS/10.0
status: 200
vary: Origin
x-powered-by: ASP.NET
Request Headers:
:authority: localhost:44364
:method: POST
:path: /api/Login/GetDataBases
:scheme: https
accept: application/json, text/plain, */ *
accept-encoding: gzip, deflate, br
accept-language: es-ES,es;q=0.9
access-control-allow-credentials: true
access-control-allow-headers: Content-type, Accept
access-control-allow-origin: *
cache-control: no-cache
content-length: 1
content-type: application/json
origin: http://localhost:3000
referer: http://localhost:3000/
sec-fetch-dest: empty
sec-fetch-mode: cors
sec-fetch-site: cross-site
user-agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/85.0.4183.83 Safari/537.36
Request Payload:
1
No properties
Response:
This request has no response data available.

I suspect that it could be because of CORS.
As you mentioned, the most of requests that ReactJS client send can get expected data, in my view, the issue would not be caused by CORS.
But configuring with both AllowAnyOrigin and AllowCredentials methods is insecure and not recommended, you can specify the allowed origins using WithOrigins method.
sometimes (about 1 in 100 times) the response status is 200 but the data is an empty string.
Based on your code, it seems that you host the app on local, to troubleshoot the issue, you can set break point inside your action method, then debug and trace the id_search and List_data.
Besides, if you host your app on server, to troubleshoot the issue, you can try to write application logs then check application logs to find useful info.
private readonly ILogger _logger;
public SomeApiController(ILogger<SomeApiController> logger)
{
_logger = logger;
}
[HttpPost("GetData")]
public IActionResult GetData([FromBody] int id_search)
{
_logger.LogInformation($"Client passed id_search is '{id_search}'");
//var List_data = YourService.GetDataById(id_search);
if (List_data.Count() < 1)
{
_logger.LogInformation($"Can not get data based on id_search '{id_search}'");
}
string json = JsonConvert.SerializeObject(List_data, Formatting.Indented);
_logger.LogInformation($"Get data based on id_search: {json}");
return Ok(json);
}

Firefox is parsing empty response payload

We're making an XHR request with the following headers (I've simplified a bit):
POST http://localhost:9001/login
Host: localhost:9001
User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:51.0) Gecko/20100101 Firefox/51.0
Accept: application/json, text/plain, */*
Content-Type: application/json;charset=utf-8
Content-Length: 67
Then our server responds like this (again simplified):
Status code: 200 OK
Cache-Control: no-cache, no-store
Connection: close
Content-Length: 0
Date: Mon, 27 Feb 2017 17:19:53 GMT
Server: WildFly/9
Set-Cookie: JSESSIONID=123; path=/
There's no payload in the response. Note the Content-Length: 0. But Firefox still tries to parse it as XML. And outputs the following error to the console:
XML Parsing Error: no root element found
Location: http://localhost:9001/login
Line Number 1, Column 1
Note, the server doesn't send a content-type header. And according to RFC 7231 it only has to send a content-type header when there is actual content.
So is this a bug in Firefox or is my research faulty?
Reproducing it yourself
I've written a small server and client to reproduce the problem.
server.js (start with node ./server.js):
const fs = require('fs'), http = require('http');
const server = http.createServer(function (request, response) {
if (request.method === 'POST') {
// send empty response
response.end();
return;
}
// send file content
fs.readFile('.' + request.url, function (error, content) {
response.writeHead(200, { 'Content-Type': request.url === '/index.html' ? 'text/html' : 'text/javascript' });
response.end(content);
});
}).listen(8080);
index.html
<script src="client.js"></script>
client.js
var xhr = new XMLHttpRequest();
xhr.open('POST', 'http://localhost:8080/login');
xhr.send();
When opening the URL http://localhost:8080/index.html in Firefox, there will be an error in the JavaScript console.
Firefox Version 51.0.1

There's no payload in the response. Note the Content-Length: 0
That means there is a payload, and that payload is 0 bytes in size. Consider the difference between null and "" as strings. What you have here is the equivalent of "" when you want the equivalent of null.
Set the status code to 204 rather than 200 to indicate you aren't sending an entity (and remove the content-type, since there's no content-type with no entity).
(For a long time Firefox would still log an error for this case, but thankfully this is finally fixed. Even when it did log the error it would still continue to run any scripts correctly).

Judging from the POST request it seems that you are using XHR/JS to send the request.
So the problem is likely in the code that is processing the result.
(Also, the Content-Type in the request is incorrect, there's no charset parameter on application/json)

JavaScript gets null response or empty responseXML from Python SimpleXMLRPCServer

I found the answer to this question. It is resolved.
Narrative: I am accessing a Python API, a set of methodCalls on top of SimpleXMLRPCServer. Server responds to browser GET request with a html page, "web_interface.html". The HTML page is a very simple script that sends a XHR POST request of xml params to the XMLRPC server. Server responds to XHR POST with headers but empty document. Server responds to cURL with correct data. Why is JavaScript not getting any readable data in response from server?
| web_interface.html |
<!DOCTYPE html>
<html>
<head>
<script>
var xrequest = '<?xml version="1.0?"><methodCall><methodName>helloWorld<methodName><params><param><firstWord><string>hello</string><firstWord></param><param><secondWord><string>world</string></secondWord></param></params></methodCall>';
function hello() {
var xhr = new XMLHttpRequest();
xhr.onreadystatechange = function() {
if (this.readyState == XMLHttpRequest.DONE) {
alert(this.responseText);
alert(this.status);
alert(this.response);
}
}
xhr.open('POST', '/', true);
xhr.setRequestHeader("Authorization", "Basic " + "aGVsbG8=" + ":" + "dGVzdA==");
xhr.send(xrequest);
}
</script>
</head>
<body>
<div>
<h2 id="msgoutput">HelloWorld API Test</h2>
<button type="button" onclick="hello(); return false;">SAY HELLO!</button>
</div>
</body>
</html>
Note: Clicking the button produces the alert dialogs. Status dialog shows "200" while Text and response dialogs are null.
| Mozilla Inspector Data & Headers |
POST Raw Data:
<?xml version="1.0?"><methodCall><methodName>helloWorld<methodName><params><param><firstWord><string>hello</string><firstWord></param><param><secondWord><string>world</string></secondWord></param></params></methodCall>
Response Headers:
Content-Length 332
Content-Type text/html
Date Sat, 10 Dec 2016 23:51:21 GMT
Server BaseHTTP/0.3 Python/2.7.12
Request Headers:
Accept text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Encoding gzip, deflate
Accept-Language en-US,en;q=0.5
AuthorizationBasic aGVsbG8=:dGVzdA== (not my actual creds, swapped fakes)
Connection keep-alive
Content-Length 218
Content-Type text/plain;charset=UTF-8
DNT1
Hostlocalhost:8442
Referer http://localhost:8442/
User-Agent Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:50.0) Gecko/20100101 Firefox/50.0
| Test with cURL |
:~$ curl -i --data '<?xml version="1.0"?><methodCall><methodName>helloWorld</methodName><params><param><firstWord><string>hello</string></firstWord></param><param><secondWord><string>world</string></secondWord></param></params></methodCall>' http://username:password#localhost:8442
HTTP/1.0 200 OK
Server: BaseHTTP/0.3 Python/2.7.12
Date: Sun, 11 Dec 2016 00:00:13 GMT
Content-type: text/html
Content-length: 137
<?xml version='1.0'?>
<methodResponse>
<params>
<param>
<value><string>hello-world</string></value>
</param>
</params>
</methodResponse>
Note: No problem, cURL returns the XML response as text. I pointed cURL at a netcat socket to see exactly what it is sending to the XMLRPC server. Here's what netcat shows when cURL hits:
| cURL POST Data |
POST / HTTP/1.1
Host: localhost:8442
Authorization: Basic YWRtaW46Z2liYmVyc2g=
User-Agent: curl/7.47.0
Accept: */*
Content-Length: 220
Content-Type: application/x-www-form-urlencoded
<?xml version="1.0"?><methodCall><methodName>helloWorld</methodName><params><param><firstWord><string>hello</string></firstWord></param><param><secondWord><string>world</string></secondWord></param></params></methodCall>
It's not CORS. Already tested a GET request to xhr.responseText with same browser on same machine. Setup is using same host, same port, same directory for both the GET page and the XHR POST XMLRPC request.
What am I missing?

The Python SimpleXMLRPCServer had some code hacked into it to handle cookies. Problem is, the code couldn't handle the cookie objects when a browser makes connection. This code threw an error on each invocation. It was stopping the server from sending the response text to the browser. I learned this after writing a Python snippet to output debug information to a file. I removed the cookie code and then the response XML was successfully sent from the server to the browser.
I also discovered that sending the username/password from the XHR Send statement would throw an authentication error from the server. The server is expecting credentials to be in the POST header as Authentication: Basic base64 [btoa(username:password)].
The content-type header was not the culprit in this case. Now content-type is set to text/xml on both client and server.
Here is the modified JavaScript code that works:
<!DOCTYPE html>
<html>
<head>
<script>
var xrequest = '<?xml version="1.0"?><methodCall><methodName>helloWorld</methodName><params><param><firstWord><string>hello</string></firstWord></param><param><secondWord><string>world</string></secondWord></param></params></methodCall>';
function hello() {
var xhr = new XMLHttpRequest();
xhr.onreadystatechange = function() {
if (this.readyState == XMLHttpRequest.DONE) {
}
}
xhr.open("POST", "/", true);
xhr.setRequestHeader("Authorization", "Basic " + btoa("admin" + ":" + "1234"));
xhr.setRequestHeader("Content-Type", "text/xml")
xhr.send(xrequest);
}
</script>
</head>
<body>
<div>
<h2 id="msgoutput">HelloWorld API Test</h2>
<button type="button" onclick="hello(); return false;">SAY HELLO!</button>
</div>
</body>
</html>

HTML form submit giving 400 bad request

I'm submitting a HTML form to REST(eXist db) web service using POST method.A normal submission is giving 400 bad request
Here is my HTML code
<html>
<script type="text/javascript">
/* function createXMLHttpRequest()
{
if( typeof XMLHttpRequest == "undefined" )
XMLHttpRequest = function()
{
try
{
return new ActiveXObject("Msxml2.XMLHTTP.6.0")
}
catch(e) {}
try
{
return new ActiveXObject("Msxml2.XMLHTTP.3.0")
}
catch(e) {}
try
{
return new ActiveXObject("Msxml2.XMLHTTP")
}
catch(e) {}
try
{
return new ActiveXObject("Microsoft.XMLHTTP")
}
catch(e) {}
throw new Error( "This browser does not support XMLHttpRequest." )
};
return new XMLHttpRequest();
}
var AJAX = createXMLHttpRequest();*/
function submitForm()
{
//AJAX.open("POST",'http://localhost:8899/exist/rest/db/xql/sample.xq');
// AJAX.send(document.form.xmlData.value);
document.form.submit();
};
</script>
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8" />
</head>
<body>
<form name='form' action="http://localhost:8899/exist/rest/db/xql/sample.xq" enctype="text/plain" method="post">
<input type="text" name="xmlData"/>
<input type="button" value="Submit" onclick="submitForm()";>
</form>
</body>
</html>
The commented code is to send POST request using AJAX.
I captured the http header request and response for form submit and AJAX submit
These are the request headers:
HTML form submit header:
(Request-Line) POST /exist/rest/db/xql/sample.xq HTTP/1.1
Host localhost:8899
User-Agent Mozilla/5.0 (Windows NT 5.1; rv:12.0) Gecko/20100101 Firefox/12.0
Accept text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language en-us,en;q=0.5
Accept-Encoding gzip, deflate
Connection keep-alive
Content-Type text/plain
Content-Length 26
AJAX request header:
(Request-Line) POST /exist/rest/db/xql/sample.xq HTTP/1.1
Host localhost:8899
User-Agent Mozilla/5.0 (Windows NT 5.1; rv:12.0) Gecko/20100101 Firefox/12.0
Accept text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language en-us,en;q=0.5
Accept-Encoding gzip, deflate
Connection keep-alive
Content-Length 16
Content-Type text/plain; charset=UTF-8
Origin null
Pragma no-cache
Cache-Control no-cache
Im not getting what's wrong in my code .
Im working on this for 2 days but i din't find any solution.
Please look into this and provide a solution.
Thanks in advance.

I'm pretty sure it's because you're sending only the value in your data.
You need to send a name = value pair.

Your code sumbits data to the server as it should be. There must be some problem with your server side code.
Quoting from checkupdown.com about error 400
400 errors in the HTTP cycle
1.Any client (e.g. your Web browser or our CheckUpDown robot) goes through the following cycle:
2.Obtain an IP address from the IP name of the site (the site URL without the leading 'http://'). This lookup (conversion of IP name to IP address) is provided by domain name servers (DNSs).
3.Open an IP socket connection to that IP address.
4.Write an HTTP data stream through that socket.
5.Receive an HTTP data stream back from the Web server in response. This data stream contains status codes whose values are determined by the HTTP protocol. Parse this data stream for status codes and other useful information.
This error occurs in the final step above when the client receives an HTTP status code it recognises as '400'.

Does your target accept POST requests, or only GET?

But you aren't sending any parameters with the Ajax POST?
The Ajax code should look something like this:
var xmlData=encodeURIComponent(document.getElementById("xmlData").value);
var parameters="xmlData="+xmlData;
AJAX.open("POST", "'http://localhost:8899/exist/rest/db/xql/sample.xq", true)
AJAX.setRequestHeader("Content-type", "application/x-www-form-urlencoded")
AJAX.send(parameters)

Only GET working in cross domain API request with django-piston

I'm not able to do POST/PUT/DELETE cross-domain request on my API using django-piston, I've CORS enabled using this script (based on this):
class CORSResource(Resource):
"""
Piston Resource to enable CORS.
"""
# headers sent in all responses
cors_headers = [
('Access-Control-Allow-Origin', '*'),
('Access-Control-Allow-Headers', 'AUTHORIZATION'),
]
# headers sent in pre-flight responses
preflight_headers = cors_headers + [
('Access-Control-Allow-Methods', '*'),
('Access-Control-Allow-Credentials','true')
]
def __init__(self, handler, authentication=None):
super(CORSResource, self).__init__(handler, authentication)
self.csrf_exempt = getattr(self.handler, 'csrf_exempt', True)
def __call__(self, request, *args, **kwargs):
request_method = request.method.upper()
# intercept OPTIONS method requests
if request_method == "OPTIONS":
# preflight requests don't need a body, just headers
resp = HttpResponse()
# add headers to the empty response
for hk, hv in self.preflight_headers:
resp[hk] = hv
else:
# otherwise, behave as if we called the base Resource
resp = super(CORSResource, self).__call__(request, *args, **kwargs)
# slip in the headers after we get the response
# from the handler
for hk, hv in self.cors_headers:
resp[hk] = hv
return resp
#property
def __name__(self):
return self.__class__.__name__
In the frontend I'm using Backbone with JSONP activated. I don't have any errors, the OPTIONS request works fine then nothing happens. I tried to change the « Access-Control-Allow-Methods » but it doesn't change anything. Any idea ?
Edit:
Here is the request headers of an OPTIONS request:
OPTIONS /api/comments/ HTTP/1.1
Host: apitest.dev:8000
User-Agent: Mozilla/5.0 (X11; Linux i686; rv:12.0) Gecko/20100101 Firefox/12.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-us,en;q=0.5
Accept-Encoding: gzip, deflate
DNT: 1
Connection: keep-alive
Origin: http://3l-oauth.dev:1338
Access-Control-Request-Method: POST
Access-Control-Request-Headers: authorization,content-type
Pragma: no-cache
Cache-Control: no-cache
and the response headers:
HTTP/1.0 200 OK
Date: Sat, 12 May 2012 09:22:56 GMT
Server: WSGIServer/0.1 Python/2.7.3
Access-Control-Allow-Methods: *
Access-Control-Allow-Credentials: true
Access-Control-Allow-Origin: *
Access-Control-Allow-Headers: AUTHORIZATION
Content-Type: text/html; charset=utf-8
X-Frame-Options: SAMEORIGIN

JSONP is GET only:
You cannot make POST, PUT, or DELETE requests cross-domain. Cross domain JavaScript is facilitated through the use of <script> tags that send requests to your server for dynamic JavaScript. script tags are GET requests only.
However, one of the recommended methods for adjusting to this limitation when dealing with cross-domain JavaScript is to use a method query parameter that you would use in your server-side code to determine how you should handle a specific request.
For instance, if the request was
POST /api/comments/
then you could do this:
/api/comments?method=POST
Under the hood, it's still a GET request, but you can achieve your goal with slight modifications to your API.
When determining the type of request, instead of checking the HTTP Method:
if request_method == "OPTIONS":
Check the request parameter "method" instead:
if request.GET["method"] == "OPTIONS":
JSONP Requests Must return JavaScript:
The other really important point to take note of is that your JSONP requests must all return JavaScript wrapped (or padded) in a function call. Since the requests are made under the hood by script tags that expect JavaScript, your server must return content that the browser understands.
If this doesn't make sense to you or you need more information, there is a great explanation here on how JSONP and script tag remoting works under the hood.