https://github.com/ryhkml/exception-filter
Throwing HTTP exception in Nginx
https://github.com/ryhkml/exception-filter
c errors http linux nginx
Last synced: 6 months ago
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Throwing HTTP exception in Nginx
- Host: GitHub
- URL: https://github.com/ryhkml/exception-filter
- Owner: ryhkml
- License: mit
- Created: 2025-02-11T13:47:11.000Z (about 1 year ago)
- Default Branch: main
- Last Pushed: 2025-04-04T06:54:57.000Z (about 1 year ago)
- Last Synced: 2025-04-04T07:32:46.453Z (about 1 year ago)
- Topics: c, errors, http, linux, nginx
- Language: C
- Homepage:
- Size: 52.7 KB
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# Exception Filter
An exception-filter is a process that handles specific errors.
This concept is based on [NestJS](https://docs.nestjs.com/exception-filters). However, in this implementation, exception-filter simply returns an HTTP response without content.
By default, it returns a status code of 204. To return a different status code, use `/:status` as the HTTP status code value.
For example: `http://127.0.0.1:10030/500`
## Example in Nginx
Instead of using Nginx's default error page, you can implement exception-filter in Nginx as follows
```
# /etc/nginx/conf.d/status-code-error.conf
error_page 500 501 504 505 506 507 508 510 511 = @err_500;
```
When using directive [error_page](https://nginx.org/en/docs/http/ngx_http_core_module.html#error_page), http status codes 500 through 511 will use the error location named `@err_500`.
The next step is to create a proxy pass configuration that points to the exceptipn-filter URL
```
# /etc/nginx/conf.d/catch-error.conf
location @err_500 {
internal;
rewrite ^ /500$1 break;
proxy_pass http://127.0.0.1:10030;
proxy_set_header Host $host;
include /etc/nginx/conf.d/proxy.conf;
}
```
The location name `@err_500` forwards error processing to `http://127.0.0.1:10030`, which serves as the exception-filter URL.
Then, simply include it in the domain configuration section below
```conf
# /etc/nginx/sites-available/domain.com.conf
server {
listen 443 ssl;
listen [::]:443 ssl;
http2 on;
server_name ;
include /etc/nginx/conf.d/status-code-error.conf;
ssl_certificate ...;
ssl_certificate_key ...;
location / {
proxy_pass http://;
proxy_set_header Host $host;
include /etc/nginx/conf.d/proxy.conf;
}
include /etc/nginx/conf.d/catch-error.conf;
}
# For 3xx redirects
server {
listen 80;
listen [::]:80;
server_name ;
include /etc/nginx/conf.d/redirect.conf;
location / {
return 301 https://$request_uri;
}
include /etc/nginx/conf.d/catch-redirect.conf;
}
```
```
# /etc/nginx/nginx.conf
...
...
...
http {
charset utf-8;
...
...
...
# This section is crucial, just create a dummy certificate using OpenSSL.
# The server block configuration below is for production.
server {
listen 80 default_server;
listen [::]:80 default_server;
listen 443 ssl default_server;
listen [::]:443 ssl default_server;
http2 on;
server_name _;
include /etc/nginx/conf.d/status-code-error.conf;
ssl_certificate /etc/nginx/tls-dummy/fullchain.pem;
ssl_certificate_key /etc/nginx/tls-dummy/cert-key.pem;
include /etc/nginx/conf.d/catch-error.conf;
return 444;
}
# Comment out the server block configuration above and use the server block configuration below.
# The server block configuration below is for the HTTP-01 challenge, a method to verify domain ownership during certificate issuance.
#server {
# listen 80 default_server;
# listen [::]:80 default_server;
#
# server_name _;
#
# location / {
# root /usr/share/nginx/html;
# index index.html index.htm;
# }
#}
include /etc/nginx/sites-available/domain.com.conf
}
```
In the above configuration example, if your Nginx returns a 5xx error, it will use the exception-filter to return an error response.
You can also add 4xx errors in the same way as the 5xx error example above.
> [!NOTE]
>
> Make sure to use the latest version of Nginx.
## Build and Usage
```sh
gcc -o nob nob.c
./nob
```
There is a list of options available:
| Option | Default Value | Description |
| -------------- | ------------- | ----------------------------------------------------------------- |
| `-h`, `--help` | | Display help message |
| `--max-conn` | 16 | Specify backlog queue size for the socket |
| `--max-queue` | 256 | Specify task in queue in thread pool |
| `--max-thread` | CPU(s) | Specify worker threads that can run simultaneously in thread pool |
| `--port` | 10030 | Specify exception-filter port |
```sh
out/exception-filter --port
```
## Formatter
`.clang-format` is based on [Google](https://google.github.io/styleguide/cppguide.html) style guide
```
BasedOnStyle: Google
IndentWidth: 4
ColumnLimit: 120
AlignArrayOfStructures: Left
AlignAfterOpenBracket: Align
BracedInitializerIndentWidth: 4
```