In the case that there is a need to post to a different domain by using JavaScript, you may see CORS issue with error such as:
XMLHttpRequest cannot load https://xyz. Response to preflight request doesn't pass access control check: No
'Access-Control-Allow-Origin' header is present on the requested resource.
Origin 'http://localhost' is therefore not allowed
access.
|
XMLHttpRequest cannot load https://xyz. request header field content-type
is not allowed by access-control-allow-headers in preflight response.
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When you search this issue and many will suggest adding a header:
"Access-Control-Allow-Origin", "*"
However this is not enough, the following is a code from Swagger example that should be able to handle normal situations:
package
io.swagger.sample.util;
import
java.io.IOException;
import
javax.servlet.*;
import
javax.servlet.http.HttpServletResponse;
public class
ApiOriginFilter implements javax.servlet.Filter {
@Override
public void doFilter(ServletRequest
request, ServletResponse response,
FilterChain chain) throws IOException,
ServletException {
HttpServletResponse res = (HttpServletResponse)
response;
res.addHeader("Access-Control-Allow-Origin", "*");
res.addHeader("Access-Control-Allow-Methods", "GET,
POST, DELETE, PUT");
res.addHeader("Access-Control-Allow-Headers",
"Content-Type");
chain.doFilter(request, response);
}
@Override
public void destroy() {
}
@Override
public void init(FilterConfig filterConfig)
throws ServletException {
}
}
|
Here is another suggestion:
response.addHeader("Access-Control-Allow-Origin", "*");response.addHeader("Access-Control-Allow-Methods", "GET, POST, OPTIONS, PUT");response.addHeader("Access-Control-Allow-Credentials", "true");response.addHeader("Access-Control-Allow-Headers","Origin, X-Atmosphere-tracking-id, X-Atmosphere-Framework, X-Cache-Date, Content-Type, X-Atmosphere-Transport, *");response.addHeader("Access-Control-Request-Headers","Origin, X-Atmosphere-tracking-id, X-Atmosphere-Framework, X-Cache-Date, Content-Type, X-Atmosphere-Transport, *");
|
A web page to test RESTFUL JSON post:
<!DOCTYPE html>
<html lang="en">
<head>
<title>RESTFUL API TEST</title>
<script type="text/javascript"
src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<script type="text/javascript"
src="https://cdnjs.cloudflare.com/ajax/libs/json2/20160511/json2.min.js"></script>
</head>
<body>
<div class="container">
<h1>RESTFUL SERVICE ENDPOINT</h1>
<form id="form"
enctype='application/json' method="post"
action="https://hostname:port/myapp/v3/api/endpoint">
<fieldset>
<legend>Enter sessionid
and username</legend>
<label>session id</label>
<input name="sessionid"
id="sessionid" type="text">
<label>username</label>
<input name="username"
id="username" type="text">
<button class="btn"
id="submit" type="submit">submit</button>
</fieldset>
</form>
</div>
<div class="container">
<fieldset>
<legend>Response</legend>
<label>status</label><input name="status"
id="status" type="text">
<p>
<textarea id="responseJson"
name="responseJson" rows="8" cols="80"></textarea>
</fieldset>
</div>
<script type="text/javascript">
$("form").submit(function(e) {
// stop the regular form
submission
e.preventDefault();
// collect the form data while
iterating over the inputs
var data = {};
for (var i = 0, ii =
form.length; i < ii; ++i) {
var input = form[i];
if (input.name) {
data[input.name] =
input.value;
}
}
// construct an HTTP request
var xhr = new XMLHttpRequest();
xhr.open(form.method,
form.action, true);
xhr.setRequestHeader('Content-Type', 'application/json;
charset=UTF-8');
xhr.onreadystatechange = function() {
$("input[name='status']").val(xhr.status);
if (xhr.readyState
=== 4
&&
(xhr.status === 201
||
xhr.status === 400 || xhr.status === 500)) {
console.log(xhr.responseText);
$("textarea[name='responseJson']").val(
xhr.responseText);
}
};
// send the collected data as JSON
xhr.send(JSON.stringify(data));
});
</script>
</body>
</html>
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Sometimes, more constraints may be required to limit the domains that could access the resource:
response.addHeader("Access-Control-Allow-Origin", "myhost.mydomain"); |
