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Author: TMoMoreau

docs/how-to/websites-on-ipfs/redirects-file-support.md

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+---
+title: redirects file support
+description: What the _redirect file is and how to use them with a website on IPFS.
+---
+# `_redirects` file support
+
+The `_redirects` file provides support for URL redirects and rewrites for websites hosted on Subdomain or DNSLink gateways. This feature enables support for single-page applications, progressive web applications, custom 404 pages, and avoids link rot when moving to IPFS-backed hosting. As well as the ability to change the appearance of a URL, change where content is located without breaking existing links, and enable URL rewriting.
+
+This `_redirects` implementaion is a subset of pre-existing standards supported by [Cloudflare](https://developers.cloudflare.com/pages/platform/redirects) and [Netlify](https://docs.netlify.com/routing/redirects/).
+
+For more detailed information, check out the [`_redirects` file support specs](https://github.com/ipfs/specs/pull/290).
+
+# Supported HTTP status codes
+
+* `200` - OK (redirect will be treated as a rewrite, returning OK without changing the URL shown in the browser).
+* `301` - Permanent redirect (the default status).
+* `302` - Found (commonly used for temporary redirects).
+* `404` - Not found (can be used redirect to custom 404 pages).
+* `410` - Gone (the requested content has been permanently removed).
+* `451` - Unavailable for legal reasons.
+
+# How to set up the `_redirects` file
+
+To use the `_redirects` file, there must be a file named `_redirects` stored underneath the root CID of the website. This `_redirects` file must be a text file containing one or more lines that follow the format explained below.
+
+## Format of the `_redirects` file
+
+Each line contained within the `_redirects` file has 3 basic components:
+
+1. The `from` path, this specifies the path to be redirected from.
+1. The `to` path, this specifies the path to be redirected to.
+1. The `status` component, this part is optional and specifies the HTTP status code that will be returned. (301, 404, etc.)
+
+For example, if for whatever reason I wanted to temporarily redirect traffic from my home page to my index page, the `_redirects` file will contain a line that looks something like this:
+
+```
+/home /index.html 302 \n
+```
+
+The same format is used for all redirects.
+
+# Examples
+
+## Catch all and PWA/SPA support
+
+The `200` status will be treated as a rewrite, returning OK without changing the URL shown in the browser. This staus code can be used to build [Progressive Web Apps](https://en.wikipedia.org/wiki/Progressive_web_app) and [Single Page Applications](https://en.wikipedia.org/wiki/Single-page_application).
+
+```
+/home /index.html 200 \n
+```
+
+## Redirect an old URL to a new place
+
+The `301` status is a permanent redirect, this is the default status code used when no others are spcified. 
+
+```
+/index /docs.html 301 \n
+```
+
+The `302` status is commonly used for temporary redirects.
+
+```
+/home /under-construction.html 302 \n
+```
+
+## Add a custom 404 page to your website
+
+Use the `_redirects` file support to add a custom 404 page to your website.
+
+```
+/home /custom-404.html 404 \n
+```
+
+## Placeholders
+
+Placeholders are named variables that can be used to match path segments in the `from` path and inject them into the `to` path.
+
+This is useful for redirecting users to their desired content, even if their search was not completely accurate.
+
+For example, if I wanted to search for an article titled "hello world" that was written on June 15, 2022, I could search for it like this: `/posts/06/15/2022/hello-world` and be redirected to `/articles/2022/06/15/hello-world`
+
+```
+/posts/<month>/<day>/<year>/<slug> /articles/<year>/<month>/<day>/<slug> \n
+```
+
+# Evaluation
+
+The `_redirects` file  is only supported on subdomain and DNSLink gateways, which provides [unique origin per root CID](https://en.wikipedia.org/wiki/Same-origin_policy).
+
+## No forced redirects
+
+Redirect logic will only be evaluated if the requested path is not in the DAG. Any performance impact associated with checking for the existence of a `_redirects` file or evaluating redirect rules will only be incurred for non-existent paths.
+
+# Error handling
+
+If there are any errors reading or parsing the `_redirects` file, the error codes will be returned with an HTTP 500 status code.