diff --git a/blog/en/blog/2024/07/18/advanced-url-rewrite-apisix.md b/blog/en/blog/2024/07/18/advanced-url-rewrite-apisix.md new file mode 100644 index 0000000000000..187071137fa36 --- /dev/null +++ b/blog/en/blog/2024/07/18/advanced-url-rewrite-apisix.md @@ -0,0 +1,88 @@ +--- +title: Advanced URL rewriting with Apache APISIX +authors: + - name: Nicolas Fränkel + title: Author + url: https://github.com/nfrankel + image_url: https://avatars.githubusercontent.com/u/752258 +keywords: + - APISIX + - URL + - URL rewriting +description: > + I spoke at Swiss PgDay in Switzerland in late June. The talk was about how to create a no-code API with the famous PostgreSQL database, the related PostgREST, and Apache APISIX, of course. I already wrote about the idea in a previous post. However, I wanted to improve it, if only slightly. + PostgREST offers a powerful `SELECT` mechanism. To list all entities with a column equal to a value, you need the following command: curl /products?id=eq.1. +tags: [Ecosystem] +image: https://static.apiseven.com/uploads/2024/07/11/zFguMrgf_notebook-1840276.jpg +--- + + + + + +>I spoke at [Swiss PgDay](https://www.pgday.ch/2024/#schedule) in Switzerland in late June. The talk was about how to create a no-code API with the famous [PostgreSQL](https://www.postgresql.org/) database, the related [PostgREST](https://postgrest.org/), and [Apache APISIX](https://apisix.apache.org), of course. I already wrote about the idea in a [previous post](https://blog.frankel.ch/poor-man-api/). However, I wanted to improve it, if only slightly. +> +>PostgREST offers a powerful `SELECT` mechanism. To list all entities with a column equal to a value, you need the following command: + + + +```bash +curl /products?id=eq.1 +``` + +1. `id` is the column +2. `eq.1` corresponds to the `WHERE` clause + +In this case, the generated query is `SELECT * FROM products WHERE id=1`. + +The [query syntax](https://postgrest.org/en/v12/references/api/tables_views.html#get-and-head) is powerful and allows you to express complex queries. However, as an API designer, I want to avoid exposing users to this complexity. For example, a regular API can manage entities by their ID, _e.g._, `/products/1`. In turn, you'd expect PostgREST to be able to do the same with primary keys. Unfortunately, it doesn't treat primary keys any differently than regular columns. Apache APISIX to the rescue. + +One of APISIX's best features is to rewrite requests, _i.e._, exposing `/products/1` and forwarding `/products?id=eq.1` to PostgREST. Let's do it. + +First, we need to capture the ID of the path parameter. For this, we need to replace the regular radix tree router with the radix tree with a parameter router. + +```yaml +apisix: + router: + http: radixtree_uri_with_parameter +``` + +The next step is to rewrite the URL. We use the [proxy-rewrite](https://apisix.apache.org/docs/apisix/plugins/proxy-rewrite/) plugin for this on a `/products/:id` route. Unfortunately, using the `:id` parameter above in the regular expression is impossible. We need to copy it to a place that is accessible. To do that, before the rewriting, we can leverage the [serverless-pre-function](https://apisix.apache.org/docs/apisix/plugins/serverless/). With the plugin, you can write Lua code directly. It's an excellent alternative to a full-fledged plugin for short, straightforward snippets. + +Here's the configuration: + +```bash +curl -i http://localhost:9180/apisix/admin/plugin_configs/1 -X PUT -d ' +{ + "plugins": { + "serverless-pre-function": { + "phase": "rewrite", + "functions" : [ + "return function(_, ctx) + ctx.var.product_id = ctx.curr_req_matched.id; #1 + end" + ] + }, + "proxy-rewrite": { + "uri": "/products?id=eq.$product_id" #2 + } + } +}' +``` + +1. Copy the captured `id` variable to a place accessible to other plugins later on +2. Use it! + +Thanks to my colleague [Zeping](https://github.com/bzp2010) for pointing out the solution to me! + +You can expose the `/products/1` REST-friendly URL and let APISIX rewrite it for PostgREST. + +## Conclusion + +I've described using the `proxy-rewrite` plugin with a path variable in this post. You can reuse the same technique with multiple variables. Keep also in mind that the `serverless` plugin is a hidden jewel; it can help you with small Lua snippets before moving to a full-fledged plugin. + +**To go further:** + +* [PostgREST](https://postgrest.org/en/v12/references) +* [PostgREST tables and views](https://postgrest.org/en/v12/references/api/tables_views.html) +* [APISIX serverless plugin](https://apisix.apache.org/docs/apisix/plugins/serverless/)