--- title: libradixtree --- ### what's libradixtree? [libradixtree](https://github.com/iresty/lua-resty-radixtree), adaptive radix trees implemented in Lua for OpenResty. APISIX using libradixtree as route dispatching library. ### How to use libradixtree in APISIX? This is Lua-Openresty implementation library base on FFI for [rax](https://github.com/antirez/rax). Let's take a look at a few examples and have an intuitive understanding. #### 1. Full match ``` /blog/foo ``` It will only match `/blog/foo`. #### 2. Prefix matching ``` /blog/bar* ``` It will match the path with the prefix `/blog/bar`, eg: `/blog/bar/a`, `/blog/bar/b`, `/blog/bar/c/d/e`, `/blog/bar` etc. #### 3. Match priority Full match -> Deep prefix matching. Here are the rules: ``` /blog/foo/* /blog/foo/a/* /blog/foo/c/* /blog/foo/bar ``` | path | Match result | |------|--------------| |/blog/foo/bar | `/blog/foo/bar` | |/blog/foo/a/b/c | `/blog/foo/a/*` | |/blog/foo/c/d | `/blog/foo/c/*` | |/blog/foo/gloo | `/blog/foo/*` | |/blog/bar | not match | #### 4. Parameter match When `radixtree_uri_with_parameter` is used, we can match routes with parameters. For example, with configuration: ```yaml apisix: router: http: 'radixtree_uri_with_parameter' ``` route like ``` /blog/:name ``` will match both `/blog/dog` and `/blog/cat`. For more details, see https://github.com/api7/lua-resty-radixtree/#parameters-in-path. ### How to filter route by Nginx builtin variable Please take a look at [radixtree-new](https://github.com/iresty/lua-resty-radixtree#new), here is an simple example: ```shell $ curl http://127.0.0.1:9080/apisix/admin/routes/1 -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -i -d ' { "uri": "/index.html", "vars": [ ["http_host", "==", "iresty.com"], ["cookie_device_id", "==", "a66f0cdc4ba2df8c096f74c9110163a9"], ["arg_name", "==", "json"], ["arg_age", ">", "18"], ["arg_address", "~~", "China.*"] ], "upstream": { "type": "roundrobin", "nodes": { "39.97.63.215:80": 1 } } }' ``` This route will require the request header `host` equal `iresty.com`, request cookie key `_device_id` equal `a66f0cdc4ba2df8c096f74c9110163a9` etc. ### How to filter route by graphql attributes APISIX supports filtering route by some attributes of graphql. Currently we support: * graphql_operation * graphql_name * graphql_root_fields For instance, with graphql like this: ```graphql query getRepo { owner { name } repo { created } } ``` * The `graphql_operation` is `query` * The `graphql_name` is `getRepo`, * The `graphql_root_fields` is `["owner", "repo"]` We can filter such route out with: ```shell $ curl http://127.0.0.1:9080/apisix/admin/routes/1 -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -i -d ' { "methods": ["POST"], "uri": "/_graphql", "vars": [ ["graphql_operation", "==", "query"], ["graphql_name", "==", "getRepo"], ["graphql_root_fields", "has", "owner"] ], "upstream": { "type": "roundrobin", "nodes": { "39.97.63.215:80": 1 } } }' ``` To prevent spending too much time reading invalid graphql request body, we only read the first 1 MiB data from the request body. This limitation is configured via: ```yaml graphql: max_size: 1048576 ``` If you need to pass a graphql body which is larger than the limitation, you can increase the value in `conf/config.yaml`.