docs: write a dedicated guide for path logic

docs/.vitepress/routes/sidebar/guide.ts

@@ -96,6 +96,7 @@ export const routes: DefaultTheme.SidebarItem[] = [
         ],
       },
       { text: 'Caching', link: '/caching' },
+      { text: 'Pathing logic and baseURL', link: '/url-resolutions' },
     ],
   },
 ]

docs/guide/advanced/url-resolutions.md

@@ -0,0 +1,106 @@
+# Pathing logic in NuxtAuth
+
+This page is here to clarify how the pathing logic works in `@sidebase/nuxt-auth`.
+You can find a full overview of how URLs are handled [in the issue comment](https://github.com/sidebase/nuxt-auth/pull/913#issuecomment-2359137989) and in spec files for [`authjs` provider](https://github.com/sidebase/nuxt-auth/blob/main/tests/authjs.url.spec.ts) and [`local` provider](https://github.com/sidebase/nuxt-auth/blob/main/tests/local.url.spec.ts).
+
+## `baseURL` is a prefix
+
+It will be prepended to a path before making a call. For example,
+
+```ts
+export default defineNuxtConfig({
+  auth: {
+    baseURL: 'https://example.com/api/auth',
+
+    provider: {
+      type: 'local',
+      endpoints: {
+        // The call would be made to `https://example.com/api/auth/login`
+        signIn: { path: '/login', method: 'post' },
+      }
+    }
+  }
+})
+```
+
+## Use URL provided in `endpoints` if it is fully specified
+
+If you provide a full URL to `endpoints`, it will be used when making calls to an endpoint:
+
+```ts {9}
+export default defineNuxtConfig({
+  auth: {
+    baseURL: 'https://your.website/api',
+
+    provider: {
+      type: 'local',
+      endpoints: {
+        // This will call `https://example.com/user`
+        getSession: { path: 'https://example.com/user' },
+
+        // This will call `https://your.website/api/login`
+        signIn: { path: '/login', method: 'post' },
+      },
+    }
+  }
+})
+```
+
+## `runtimeConfig`
+
+Value of `baseURL` is always located at `runtimeConfig.public.auth.baseURL`. You cannot change it directly as of the moment of writing, but you can read the value in your application:
+
+```ts
+const runtimeConfig = useRuntimeConfig()
+const baseURL = runtimeConfig.public.auth.baseURL
+```
+
+This value is generally the [source of truth](https://github.com/sidebase/nuxt-auth/blob/b5af548c1fc390ae00496e19ad7a91d308af9b12/src/runtime/utils/url.ts#L37-L38). It is being [set in the plugin](https://github.com/sidebase/nuxt-auth/blob/b5af548c1fc390ae00496e19ad7a91d308af9b12/src/runtime/plugin.ts#L20-L24) to also be available on the client.
+
+## Changing `baseURL`
+
+Read next to understand how it can be changed.
+
+### 1. Environment variables
+
+You have multiple ways of changing the `baseURL` via env variables:
+- use `NUXT_PUBLIC_AUTH_BASE_URL`;
+- use `AUTH_ORIGIN` if `originEnvKey` is not set;
+- use the environment variable name set in [`originEnvKey`](/guide/application-side/configuration#originenvkey)
+
+Environment variables should work in both build-time and runtime.
+
+### 2. `baseURL`
+
+If you didn't set an environment variable, NuxtAuth will look for [`auth.baseURL`](/guide/application-side/configuration#baseurl) inside the `nuxt.config.ts`.
+
+Note that this variable is always **static**, will only be set during runtime and can still be overriden in runtime using env variables.
+
+Not setting `baseURL` will default to `/api/auth`.
+
+### 3. `authjs` only: determine origin automatically from the incoming `HTTP` request
+
+When the server is running in **development mode**, NuxtAuth can automatically infer `baseURL` from the incoming request.
+
+---
+
+Therefore as of version 0.10.0, we recommend the following setup to set your `AUTH_ORIGIN` or `baseURL`:
+
+::: code-group
+
+```ts diff [nuxt.config.ts]
+export default defineNuxtConfig({
+  // ... other configuration
+  auth: {
+    baseUrl: 'https://my-backend.com/api/auth', // [!code --]
+    // This is technically not needed as it is the default, but it's here for illustrative purposes
+    originEnvKey: 'AUTH_ORIGIN', // [!code ++]
+  }
+})
+```
+
+```env diff [.env]
+AUTH_ORIGIN="https://my-backend.com/api/auth" // [!code ++]
+```
+
+:::

docs/guide/local/quick-start.md

@@ -53,7 +53,7 @@ In the example above, we define a [runtime config](https://nuxt.com/docs/guide/g
 
 You can customize each endpoint to fit your needs or disable it by setting it to `false`. For example you may want to disable the `signUp` endpoint.
 
-```ts{7}
+```ts{6}
 export default defineNuxtConfig({
     auth: {
         provider: {

docs/upgrade/version-0.10.0.md

@@ -43,48 +43,33 @@ definePageMeta({
 
 ### Adjustments to the computation of `baseURL` and `AUTH_ORIGIN`
 
-In 0.10.0 we spent a considerable amount of time reworking how `@sidebase/nuxt-auth` determine which endpoints to make requests to. If you would like to view the full PR and discussion, you can find it [here](https://github.com/sidebase/nuxt-auth/pull/913).
+In 0.10.0 we spent a considerable amount of time reworking how `@sidebase/nuxt-auth` determines which endpoints to make requests to. If you would like to view the full PR and discussion, you can find it [here](https://github.com/sidebase/nuxt-auth/pull/913).
 
-As a quick overview, `@sidebase/nuxt-auth` will now use the following logic to determine where to make requests to:
+Read more [in a dedicated guide](../guide/advanced/url-resolutions.md).
 
-#### 1. Environment variable and `runtimeConfig`
+Below are some notable changes.
 
-Use the `AUTH_ORIGIN` environment variable or `runtimeConfig.authOrigin` if set. Name can be customized, refer to [`originEnvKey`](/guide/application-side/configuration#originenvkey).
+#### URLs are now joined
 
-#### 2. `baseURL`
+`baseURL` now means exactly that, it will be prepended to a path before making a call. That means you need to adjust your config accordingly:
 
-Use the static [`baseURL`](/guide/application-side/configuration#baseurl) inside the `nuxt.config.ts` if set.
-
-#### 3. Automatically from the incoming `HTTP` request
-
-When the server is running in **development mode**, NuxtAuth can automatically infer it from the incoming request.
-
----
-
-Therefore as of version 0.10.0, we recommend the following setup to set your `AUTH_ORIGIN` or `baseURL`:
-
-::: code-group
-
-```ts diff [nuxt.config.ts]
+```ts diff
 export default defineNuxtConfig({
-  // ...Previous configuration
-  runtimeConfig: { // [!code ++]
-    baseURL: '/api/auth' // [!code ++]
-  }, // [!code ++]
   auth: {
-    baseUrl: 'https://my-backend.com/api/auth', // [!code --]
-    originEnvKey: 'NUXT_BASE_URL', // [!code ++]
+    baseURL: 'https://example.com', // [!code --]
+    baseURL: 'https://example.com/api/auth', // [!code ++]
+
+    provider: {
+      type: 'local',
+      endpoints: {
+        signIn: { path: '/login', method: 'post' },
+      }
+    }
   }
 })
 ```
 
-```env diff [.env]
-NUXT_BASE_URL="https://my-backend.com/api/auth" // [!code ++]
-```
-
-:::
-
-### Adjustments when using an external backend for the `local`-provider
+#### Adjustments when using an external backend for the `local`-provider
 
 In previous versions of `@sidebase/nuxt-auth` a very specific setup was needed to ensure that external backends could properly be used for the `local` provider. In 0.10.0 we reworked the internal handling or URLs to make it more consistent across providers and configurations.
 
@@ -106,7 +91,28 @@ export default defineNuxtConfig({
 })
 ```
 
-You can find a full overview of how `@sidebase/nuxt-auth` handles URLs [here](https://github.com/sidebase/nuxt-auth/pull/913#issuecomment-2359137989) and in spec files for [`authjs` provider](https://github.com/sidebase/nuxt-auth/blob/main/tests/authjs.url.spec.ts) and [`local` provider](https://github.com/sidebase/nuxt-auth/blob/main/tests/local.url.spec.ts).
+---
+
+Therefore as of version 0.10.0, we recommend the following setup to set your `AUTH_ORIGIN` or `baseURL`:
+
+::: code-group
+
+```ts diff [nuxt.config.ts]
+export default defineNuxtConfig({
+  // ... other configuration
+  auth: {
+    baseUrl: 'https://my-backend.com/api/auth', // [!code --]
+    // This is technically not needed as it is the default, but it's here for illustrative purposes
+    originEnvKey: 'AUTH_ORIGIN', // [!code ++]
+  }
+})
+```
+
+```env diff [.env]
+AUTH_ORIGIN="https://my-backend.com/api/auth" // [!code ++]
+```
+
+:::
 
 ## Changelog