I have a Lambda function (a packaged next.js app) which I'm trying to access via CloudFront. The web app works unless I try to hit the homepage.
When I hit /search or /video/{videoId} the page loads just fine.
When I try to hit the homepage, I get the following error page:
502 ERROR
The request could not be satisfied.
The Lambda function returned invalid JSON: The JSON output is not parsable. We can't connect to the server for this app or website at this time. There might be too much traffic or a configuration error. Try again later, or contact the app or website owner.
If you provide content to customers through CloudFront, you can find steps to troubleshoot and help prevent this error by reviewing the CloudFront documentation.
Generated by cloudfront (CloudFront)
Request ID: {id}
Why would just the homepage be invalid JSON? Where can I see this JSON to determine what is wrong? I created a mock Cloudfront request test in the Lambda function and it just returns successfully.
The problem was due to the 1 MB size limit of CloudFront Lambda#Edge responses. I didn't realize that Next.js's serverside rendering was creating a large <script id="__NEXT_DATA__"> tag on my homepage with all the fetched info from my API duplicated multiple times over. This resulted in my app's homepage being >2 MB.
I refactored my app to only send one network request, and made sure that data is only put into the __NEXT_DATA__ tag once. The app now works.
to give some context I am for the first time trying to participate in a BugBounty program and I found out which cloudfront URL is serving content to a website and the content being served is in json format.
Each time I try to access the information through the url of the website I get the next message:
{"error":"You need to sign in or sign up before continuing."}
If I try to access the Cloudfront url(xxxxxxx.cloudfront.net) I get:
403 ERROR
The request could not be satisfied.
Bad request. We can't connect to the server for this app or website at this time. There might be too much traffic or a configuration error. Try again later, or contact the app or website owner.
If you provide content to customers through CloudFront, you can find steps to troubleshoot and help prevent this error by reviewing the CloudFront documentation.
Generated by cloudfront (CloudFront) and a request id
I would like to know if somebody know a good article that explains how to bypass those 403 or 401 messages and obtain the JSON output
Thank you very much for all the information provided in advance.
I'm almost complete with a new web app, however, I'm getting a 403 error from AWS's API Gateway due to a CORs issue.
I'm creating a Vue app and using Vue's axios library. CORs is enabled and the request works with API Key Required option turned off in AWS's API Gateway by sending the following:
axios
.get('My-URL-Endpoint',{headers: {})
.then(response => (this.passports = response.data ));
When I turn on API Key Required functionality inside AWS's API Gateway. It works when I use Postman along with including x-api-key: My-API-Key. However, using Vue's axios it does not work and returns error 403:
axios
.get('My-URL-Endpoint', {headers: {
'x-api-key': 'My-API-Key'
}})
.then(response => (this.passports = response.data ));
My first instinct is that the problem is related to how Axios is sending the request through the browser. From what I can gather it looks like the pre-flight check is failing because I am receiving the following error within the browser:
Access to XMLHttpRequest at 'My-URL' from origin 'http://localhost:8080' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource.
Sure enough it looks like there is no access-control-allow-origin key in the response. So I added access-control-allow-origin to the response of the 403 message and got a new error "It does not have HTTP ok status"
I've been trying nearly everything to get this to work! I came across stackoverflow answer where it seems like the person was suggesting that API Key Required Key functionality can't work with CORs. This kind of seemed like that cannot be true. It would be a pretty crippling restriction.
So my question is how to get the browser's pre-flight check to work along with CORs and API Key capability inside AWS's API Gateway?
Thank you!
If you have enabled cors on your api gateway, the next place to look is the application code such as lambda. Make sure the Lambda is returning the correct cross origin headers in both successful and failure scenarios.
First of all you can check if the request is reaching the lambda from the cloud watch logs. Another way to check this is to temporarily point the Api gateway target to the Mock end point.
If the mock endpoint works, then the problem is the application code. otherwise the problem is in your api gateway end point.
Also note that any headers you use should be white listed in the Access-Control-Allow-headers section when you enable to cors for your method/resource.
I've created an API with C++ and the following library: https://github.com/yhirose/cpp-httplib
In the API I've added a header to responses for CORS:
svr.Post("/suggest", [&dr](const Request &req, Response &res){
res.set_header("Access-Control-Allow-Origin","(origin here)");
(origin here) is the origin of the server making the request.
On the browser side I've also enabled an extension to bypass CORS. But when trying to make an AJAX request to the API, I still get this error in my browser console:
Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at https://192.168.1.10:10120/suggest. (Reason: CORS request did not succeed).
The AJAX request is done through a script written in the Tampermonkey extension to work on a specific website.
Do I need to modify headers on the server hosting the website? Have I done something wrong on the C++ side?
Also it might be important to mention that the code worked before. All I did was come back to it another day with a different local IP address (which i reprogrammed into the c++ API)
I tried it again to answer #sideshowbarker and it gave me a new error about self signed certificates. After adding the exception it worked.
For a while, I was simply storing the contents of my website in a s3 bucket and could access all pages via the full url just fine. I wanted to make my website more secure by adding an SSL so I created a CloudFront Distribution to point to my s3 bucket.
The site will load just fine, but if the user tries to refresh the page or if they try to access a page using the full url (i.e., www.example.com/home), they will receive an AccessDenied page.
I have a policy on my s3 bucket that restricts access to only the Origin Access Identity and index.html is set as my domain root object.
I am not understanding what I am missing.
To demo, feel free to visit my site.
You will notice how it redirects you to kurtking.me/home. To reproduce the error, try refreshing the page or access a page via full URL (i.e., kurtking.me/life)
Any help is much appreciated as I have been trying to wrap my head around this and search for answers for a few days now.
I have figured it out and wanted to post my solution in case anyone else runs into this issue.
The issue was due to Angular being a SPA (Single Page App) and me using an S3 bucket to store it. When you try to go to a specific page via url access, CloudFront will take (for example, /about) and go to your S3 bucket looking for that file. Because Angular is a SPA, that file doesn't technically exist in your S3 bucket. This is why I was getting the error.
What I needed to do to fix it
If you open your distribution in Cloudfront, you will see an 'Error Pages' tab. I had to add two 'Custom Error Responses' that handled 400 and 403. The details are the same for 400 and 403, so I only include a photo for 400. See below:
Basically, what is happening is you are telling Cloudfront that regardless of a 400 or 403 error, to redirect back to index.html, thus giving control to Angular to decide if it can go to the path or not. If you would like to serve the client a 400 or 403 error, you need to define these routes in Angular.
After setting up the two custom error responses, I deployed my cloudfront solutions and wallah, it worked!
I used the following article to help guide me to this solution.
The better way to solve this is to allow list bucket permission and add a 404 error custom rule for cloudfront to point to index.html. 403 errors are also returned by WAF, and will cause additional security headaches, if they are added for custom error handling to index.html. Hence, better to avoid getting 403 errors from S3 in the first place for angular apps.
If you have this problem using CDK you need to add this :
MyAmplifyApp.addCustomRule({
source: '</^[^.]+$|\.(?!(css|gif|ico|jpg|js|png|txt|svg|woff|ttf|map|json)$)([^.]+$)/>',
target: '/index.html',
status: amplify.RedirectStatus.REWRITE
});
The accepted answer seems to work but it does not seem like a good practice. Instead check if the cloudfront origin is set to S3 Bucket(in which the static files are) or the actual s3 url endpoint. It should be the s3 url endpoint and not the s3 bucket.
The url after endpoint should be the origin
Add a Cloudfront function to rewrite the requested uri to /index.html if it doesn't match a regex.
For example, if none of your SPA routes contain a "." (dot), you could do something like this:
function handler(event) {
var request = event.request
if (/^(?!.*\..*).*$/.test(request.uri)) {
request.uri = '/index.html'
}
return request
}
This gets around any kind of side effects you would get by redirecting 403 -> index.html. For example, if you use a WAF to restrict access by IP address, if you try to navigate to the website from a "bad IP", a 403 will be thrown, but with the previously suggested 403 -> index.html redirect, you'd still see index.html. With a cloudfront function, you wont.
For those who are trying to achieve this using terraform, you only need to add this to your CloudFront Configuration:
resource "aws_cloudfront_distribution" "cf" {
...
custom_error_response {
error_code = 403
response_code = 200
response_page_path = "/index.html"
}
...
}
Please check from the console which error are you getting. In my case I was getting a 403 forbidden error, and using the settings which are shown in the screenshot worked for me