Add /info endpoint docs

docs/_sidebar.md

@@ -3,6 +3,7 @@
 * [Configuration](configuration)
 * [Generating the URL (Basic)](generating_the_url_basic)
 * [Generating the URL (Advanced)](generating_the_url_advanced)
+* [Getting the image info <img class="pro-badge" src="assets/pro.svg" alt="pro" />](getting_the_image_info)
 * [Signing the URL](signing_the_url)
 * [Watermark](watermark)
 * [Presets](presets)

docs/getting_the_image_info.md

@@ -0,0 +1,80 @@
+# Getting the image info <img class="pro-badge" src="assets/pro.svg" alt="pro" />
+
+imgproxy can fetch and return the source image info without downloading the whole image.
+
+## URL format
+
+To get the image info, use the following URL format:
+
+```
+/info/%signature/plain/%source_url
+/info/%signature/%encoded_source_url
+```
+
+### Signature
+
+Signature protects your URL from being modified by an attacker. It is highly recommended to sign imgproxy URLs in a production environment.
+
+Once you set up your [URL signature](configuration.md#url-signature), check out the [Signing the URL](signing_the_url.md) guide to learn about how to sign your URLs. Otherwise, use any string here.
+
+### Source URL
+
+There are two ways to specify source url:
+
+#### Plain
+
+The source URL can be provided as is, prepended by `/plain/` part:
+
+```
+/plain/http://example.com/images/curiosity.jpg
+```
+
+**📝Note:** If the sorce URL contains query string or `@`, you need to escape it.
+
+#### Base64 encoded
+
+The source URL can be encoded with URL-safe Base64. The encoded URL can be split with `/` for your needs:
+
+```
+/aHR0cDovL2V4YW1w/bGUuY29tL2ltYWdl/cy9jdXJpb3NpdHku/anBn
+```
+
+## Response format
+
+imgproxy responses with JSON body and returns the following info:
+
+* `format`: source image/video format. In case of video - list of predicted formats divided by comma;
+* `width`: image/video width;
+* `height`: image/video height;
+* `size`: file size. Can be zero if the image source doesn't set `Content-Length` header properly;
+* `exif`: JPEG exif data.
+
+#### Example (JPEG)
+
+```json
+{
+  "format": "jpeg",
+  "width": 7360,
+  "height": 4912,
+  "size": 28993664,
+  "exif": {
+    "Aperture": "8.00 EV (f/16.0)",
+    "Contrast": "Normal",
+    "Date and Time": "2016:09:11 22:15:03",
+    "Model": "NIKON D810",
+    "Software": "Adobe Photoshop Lightroom 6.1 (Windows)"
+  }
+}
+```
+
+#### Exampple (mp4)
+
+```json
+{
+  "format": "mov,mp4,m4a,3gp,3g2,mj2",
+  "width": 1178,
+  "height": 730,
+  "size": 984963,
+  "exif": {}
+}
+```

docs/signing_the_url.md

@@ -22,8 +22,9 @@ echo $(xxd -g 2 -l 64 -p /dev/random | tr -d '\n')
 Signature is an URL-safe Base64-encoded HMAC digest of the rest of the path, including the leading `/`. Here is how it is calculated:
 
 * Take the path part after the signature:
-  * For [basic URL format](generating_the_url_basic.md): `/%resizing_type/%width/%height/%gravity/%enlarge/%encoded_url.%extension`;
-  * For [advanced URL format](generating_the_url_advanced.md): `/%processing_options/%encoded_url.%extension`;
+  * For [basic URL format](generating_the_url_basic.md): `/%resizing_type/%width/%height/%gravity/%enlarge/%encoded_url.%extension` or `/%resizing_type/%width/%height/%gravity/%enlarge/plain/%plain_url@%extension`;
+  * For [advanced URL format](generating_the_url_advanced.md): `/%processing_options/%encoded_url.%extension` or `/%processing_options/plain/%plain_url@%extension`;
+  * For [info URL](getting_the_image_info.md): `/%encoded_url` or `/plain/%plain_url`;
 * Add salt to the beginning;
 * Calculate the HMAC digest using SHA256;
 * Encode the result with URL-safe Base64.