Add proxy instructions

readme.md

@@ -254,6 +254,36 @@ For example, for the previous image, the link to the full image would be `/img/f
 
 The `/img/` path serves all images directly from disk. Mitsuba looks in your `DATA_ROOT` folder, which is `data` by default, and serves the `images` folder within from this path (`/img/`). So you can find all the images in there.
 
+## Proxies 
+Mitsuba can be configured to use one or multiple proxies for requests to 4chan's API as well as the image fetching.
+The load balancing system distributes the requests between them, allowing you to circumvent 4chan's rate limiting.
+This is mainly intended for when it's strictly necessary, for example when 4chan is under DDoS attack which results in Cloudflare rate limiting clients to a degree that causes issues for archivers. This feature should not be used to abuse 4chan's API.
+
+In order to add proxies, you need to set environment variables `PROXY_URL_{N}` to the URLs of the proxies you intend to use, where N is a number
+starting from 0 for the first proxy, then 1 for the second, etc.
+For example:
+```
+PROXY_URL_0=socks5://user:password@example.com:1337
+PROXY_URL_1=socks5://user:password@10.0.0.2:1337
+```
+You have to start from 0 and not skip any numbers, or some or all of the proxies will not be detected.
+You can set a weight for each proxy, this is an integer that determines how often it is used in relation to the others.
+```
+PROXY_WEIGHT_0=3
+PROXY_WEIGHT_1=1
+```
+By default, even if you have set up proxies, Mitsuba **will** also use your machine's regular IP address (bypassing any proxies) alongside the proxies you configured, treating it as if it was a proxy with weight 1. Meaning that, if you set up two proxies, mitsuba will alternate between proxy 0, proxy 1 and not using any proxy for requests, based on the assigned weights.
+This can be configured with `PROXY_ONLY`. If set to true, all requests will be routed through the proxies.
+The weight of your own IP address as a "proxy" in load balancing can be set with `PROXY_WEIGHT_SELF`:
+```
+PROXY_ONLY=false
+PROXY_WEIGHT_SELF=2
+```
+Note that the underlying HTTP library we use employs connection pooling. This means that the same connection to the server can be reused many times.
+Whenever a connection is reused, the proxy will be the same as for the previous request that used the same connection. So, which proxy is used is only decided when a new connection is created, rather than whenever a request is made.
+This means that the weights don't determine exactly how often the proxy is used to make requests, instead they determine how often they are used to open a new connection. Since connections can be reused any number of times, there is no guarantee that all proxies you configured will be used.
+
+
 ## Commands
 Use `mitsuba help` to get a list of commands and their descriptions, `mitsuba help COMMAND` to see the options specific to each command.