docs: change api response format from objects to arrays

a possibly better data format to work with in javascript.

README.md

@@ -6,10 +6,39 @@ such proxies to reduce IP address leaks and client fingerprinting.
 
 ## API v1
 
-there's a single endpoint accepting a nostr event id and relay to fetch the event from:
+over HTTP, noxy exposes a single endpoint accepting a nostr event id and
+a relay to fetch the event from:
 
     GET /api/v1/e/<event-id>?relay=<relay-uri>
 
+the response is an array of objects:
+
+```json
+[
+  {
+    "url": "<original url>",
+    "cache": "<noxy url>",
+    "kind": "media|preview",
+    "size": 123,
+    "title": "resource title",
+    "descr": "resource description"
+  }
+]
+```
+
+where `url` is the original url found in a nostr event payload and `cache` is the
+proxied url or a link preview image. the other fields presence and their values
+depend on the `kind` of the resource.
+
+for images, videos and audio the `kind` field is `media` and the `size` is the
+file size in bytes as stored in cache. if the file size is unknown at the time
+of a response, it is 0.
+
+for link previews, the `kind` field is `preview`, `cache` url points to a link
+preview image and the `size` is the preview image size. link preview image,
+`title` and `descr` field values are collected using
+[the open graph protocol](https://ogp.me/) or [oEmbed](https://oembed.com/).
+
 some examples follow.
 
 ### fetch a pubkey profile picture, event kind 0
@@ -22,21 +51,22 @@ request example:
 response:
 
 ```json
+[
   {
-  "images": {
-    "https://git.qcode.ch/avatars/5a8071777eba7ebf178143fa650c8012?size=870": "https://noxy.example.org/abcdef/abcdef0123456789.png"
-  }
+    "url": "https://git.qcode.ch/avatars/5a8071777eba7ebf178143fa650c8012?size=870",
+    "cache": "https://noxy.example.org/abcdef/abcdef0123456789.png",
+    "kind": "media",
+    "size": 279342
   }
+]
 ```
 
 [event raw data &rightarrow;](https://nostr.com/e/e01ac1cfc5cb68b54183f878261b21ef30a65f5e06a24356cfe3ecdacce14bae)
 
-if a noxy instance is unable to fetch the original, it responds with an empty object:
+if a noxy instance is unable to fetch the original, it responds with an empty array:
 
 ```json
-{
-  "images": {}
-}
+[]
 ```
 
 ### fetch images from a text note, event kind 1
@@ -48,11 +78,14 @@ request example:
 response:
 
 ```json
+[
   {
-  "images": {
-    "https://res.cloudinary.com/eskema/image/upload/v1668636521/osso_vt7qh7.png": "https://noxy.example.org/fedcba/fedcba9876543210.png"
-  }
+    "url": "https://res.cloudinary.com/eskema/image/upload/v1668636521/osso_vt7qh7.png",
+    "cache": "https://noxy.example.org/fedcba/fedcba9876543210.png",
+    "kind": "media",
+    "size": 93241
   }
+]
 ```
 
 [event raw data &rightarrow;](https://nostr.com/e/d822fdd220d8a74d2f025f331840eec8a640a663f1d3ca3de9f6a74ff0cc61fa)
@@ -66,23 +99,16 @@ request example:
 response:
 
 ```json
+[
   {
-  "links": {
-    "https://github.com/fiatjaf/noscl/pull/24": {
-      "og:image": "https://opengraph.githubassets.com/dc27...92c8/fiatjaf/noscl/pull/24",
-      "og:image:alt": "if the  arg to publish or message command is '-', it is read from stdin.\ncloses #19",
-      "og:image:width": "1200",
-      "og:image:height": "600",
-      "og:site_name": "GitHub",
-      "og:type": "object",
-      "og:title": "publish,message: accept content from stdin by x1ddos · Pull Request #24 · fiatjaf/noscl",
-      "og:description": "if the  arg to publish or message command is '-', it is read from stdin.\ncloses #19"
-    }
-  },
-  "images": {
-    "https://opengraph.githubassets.com/dc27...92c8/fiatjaf/noscl/pull/24": "https://noxy.example.org/beef01/beef0123456789.png"
-  }
+    "url": "https://github.com/fiatjaf/noscl/pull/24",
+    "cache": "https://noxy.example.org/beef01/beef0123456789.png",
+    "kind": "preview",
+    "size": 110480,
+    "title": "publish,message: accept content from stdin by x1ddos · Pull Request #24 · fiatjaf/noscl",
+    "descr": "if the arg to publish or message command is '-', it is read from stdin.\ncloses #19"
   }
+]
 ```
 
 [event raw data &rightarrow;](https://nostr.com/e/af30dac1d800acc25b87d0d6d0dd33bddf49e7f356556540a6c7722e3cb363fe)