I am trying to build a little website where i need to use Docxtemplater. (https://docxtemplater.com/)
This is a node module used to edit word documents (.docx). In the docs (https://docxtemplater.com/docs/generate/), it is stated "Please note that if you want to load a docx from your filesystem, you will need a webserver or you will be blocked by CORS policy."
I have tried uploading my website to a host (https://www.000webhost.com/), but i get the error:
mathiastester.000webhostapp.com/:1 Access to XMLHttpRequest at 'https://docxtemplater.com/tag-example.docx' from origin 'https://mathiastester.000webhostapp.com' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.
Does anyone have any clue on what is going on...?
Here is the website: https://mathiastester.000webhostapp.com/
Just like the example in the link you provided, your AJAX code needs to make a request to some server-side code running on your webserver, which then sends the request to docxtemplater, because docxtemplater doesn't allow cross-origin ("CORS") requests to it.
Simply put, a CORS request is an AJAX request where the request is sent to a different "origin" (combination of domain, port and protocol) than the one it is running from. These are disallowed by browsers by default for security reasons, but the remote server can, if it wishes, return response headers indicating to the browser that the request can in fact be allowed. docxtemplater doesn't do that, and the documentation you quoted is telling you not to make a CORS request to their servers. However judging by the error message you've shown us, you've done exactly that in your code.
See https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS for more info on what CORS is.
Related
I have a small Django project running on a ubuntu server with NGINX and gunicorn.
Everything works great when users visit www.example.com, However, when a user visits example.com instead of www.example.com, this is where it falls apart. I am using some javascript with the fetch command, to get data from my API (Django REST) and it returns:
Access to fetch at 'https://www.example.com/builds/apidata/4'
from origin 'https://example.com' has been blocked by CORS
policy: No 'Access-Control-Allow-Origin' header is present on the requested
resource. If an opaque response serves your needs, set the request's mode to
'no-cors' to fetch the resource with CORS disabled.
The easiest solution I have found is to just remove example.com from my ALLOWED_HOSTS in my settings.py file, but then when users forget www. they will be greeted with a 404 error.
The CORS error message also states I can change the request mode, but I don't know the security implications of this..
I also tried to use redirection on my domain settings from example.com to www.example.com, but this doesn't seem work either.
Any suggestions would be appreciated!
Although you could certainly use CORS to allow this cross-domain usage, a simpler and cleaner solution is to just allow one root domain—either with www or not.
Setting PREPEND_WWW to True is a simple way to ensure that requests consistently use the www version, as it causes CommonMiddleware to issue redirects when the non-www version is used.
In your webserver configuration, you can add an Access-Control-Allow-Origin header on your www subdomain, which would allow requests from your root domain.
This would work: Access-Control-Allow-Origin: https://example.com
I have a web method that I want to call from my C# app and was provided with a Javascript example, showing how to call the method. I have established that running the Javascript from my desktop runs into CORS problems - i was able to run the sample when I put the javascript on the server and ran it from the same folder as the web method.
Will my C# app run into the same CORS issue? or will it be ok because only the browsers have the built in CORS security?
--Edit--
I've been using System.Net.Http.HttpClient and http://restsharp.org/
Am I correct in assuming that these two objects are wrappers around a web browser? and that they will have issues with CORS?
I really don't want to have to write Sockets code.
Due to security reasons browsers restrict cross-origin HTTP requests initiated from within scripts on the browser. For example, XMLHttpRequest follows the same-origin policy. That means a web application using XMLHttpRequest could only make HTTP requests to its own domain. This prevents application from being vulnerable to CSRF attacks. However, there are cases when applications need to access resources from different domain. This is when CORS comes into play to allow cross-domain requests.
Having said all that, your C# app should be able to call the WEB API without any CORS issues as long as it's a socket to socket communication (not via browser).
Some where in deep recess of my mind I remember browser related cors will always be blocked unless noted or changed like for example if you're in chrome and have the cors extension allow browser cors control, but on the server side, their is nothing preventing servers from interacting with one another.
but it depends on what is allowed on the headers
I'll try to produce some documentation that confirms that.
https://spring.io/understanding/CORS
The request includes an Origin header that indicates the origin of the client code.
The server will consider the request's Origin and either allow or disallow the request. If the server allows the request, then it will respond with the requested resource and an Access-Control-Allow-Origin header in the response. This header will indicate to the client which client origins will be allowed to access the resource. Assuming that the Access-Control-Allow-Origin header matches the request's Origin, the browser will allow the request.
On the other hand, if Access-Control-Allow-Origin is missing in the response or if it doesn't match the request's Origin, the browser will disallow the request.
I'm trying to make an ajax get call between the two following sub domains:
Target URL: https://qa.mydomain.com
Origin URL: https://myotherqa.mydomain.com
I'm receiving the following error:
XMLHttpRequest cannot load https://qa.mydomain.com/suggest?
q=foo. No 'Access-Control-Allow-Origin' header is present on the requested
resource. Origin 'https://myotherqa.mydomain.com' is therefore not allowed
access.
I'm using $.get() to make the ajax call
Both the websites are under the same sub domain and both 'https'.
What am I missing?
Thanks
Issue is related to web security aka Same origin policy.
Under the policy, a web browser permits scripts contained in a first
web page to access data in a second web page, but only if both web
pages have the same origin. An origin is defined as a combination of
URI scheme, hostname, and port number. - More info here.
The proper solution to handle this is to allow CORS on your server side.
An alternative solution is using JSONP for get requests.
You can find some common settings and more information at this site:
http://enable-cors.org/
The problem is with the server configuration the server is not accepting request from other domains for security concerns. Ports maybe different, enable the cors at the server level configuration. This will solve the issue.
guys!
I'm having some trouble with javascript in Ionic. I'm trying to make a request to another site, and I'm having this error message:
XMLHttpRequest cannot load https://svcs.sandbox.paypal.com/AdaptivePayments/Pay. 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:8100' is therefore not allowed access.
My Ionic App have already the plugin whitelist installed and up to date, my config.xml file allow navigation and access of every location. I've tried also to execute chrome with security disabled and it didn't work either.
Could anyone help? Don't know what else to do.
By default, XMLHttpRequests are limited to same domain requests (i.e. request between localhost and localhost or request between paypal.com and paypal.com).
Cross-site XMLHttpRequests (like from localhost to paypal.com) are disabled by default as a security feature in modern browsers, in order to bypass this security feature, the destination server should explicitly allow cross-site requests and this is done by sending back a header called "Access-Control-Allow-Origin" with either * or specific domain as value, for example when a server replies back with the following header:
Access-Control-Allow-Origin: *
It is telling the browser of visitor that I'm accepting an XMLHttpRequest from any domain.
In your case, you are doing a request on https://svcs.sandbox.paypal.com/AdaptivePayments/Pay which doesn't allow cross-site requests (no Access-Control-Allow-Origin is present) and thus the browser is blocking XMLHttpRequest from going through.
You cannot test your http://localhost:8100 (LOCALHOST) to paypal services/api's that requires communication with your script, except if you use tunnel hosts, like https://ngrok.com/, https://localtunnel.me/. Your scripts that run in your localhost should be accessible to the world wide web, so that it is visible to Paypal.
I'm trying to wrap my head around CORS (cross origin resource sharing) by reading https://developer.mozilla.org/en-US/docs/Web/HTTP/Access_control_CORS. Here, I noticed that the document states:
Cross-site HTTP requests initiated from within scripts have been subject to well-known restrictions, for well-understood security reasons. For example HTTP Requests made using the XMLHttpRequest object were subject to the same-origin policy.
This makes sense to me, as I have experienced the following error before:
XMLHttpRequest cannot load http://localhost:7000. No
'Access-Control-Allow-Origin' header is present on the requested
resource. Origin http://localhost:9000 is therefore not allowed
access.
However, why does curl http://localhost:7000 return the JSON that located on the page correctly? Is it simply the fact that curl commands don't come from scripts? In addition, how does the browser even recognize that the request is coming from a script? If this differentiates significantly from browser to browser, I'd be curious to know about how Chrome and Firefox detect this.
In my idea
XMLHttpRequest is javascript call server to get data and noad reload page. No page load first no XMLHttpRequest.
Curl is php server function get data from server and return to php code, curl is a part of server code.