doc: request path documentation

README.md

@@ -29,13 +29,57 @@ My first Rust project, intended to offer a simple way to display the current tim
 
 ## Routes
 
-```shell
+`GET /[relative|absolute]/[value]{.ext}?tz={timezone}&format={format_string}&now={timestamp}&static={boolean}`
-/{time}[.{ext}]
+
-/{rel|relative}/{time}[.{ext}]
+- `{relative|absolute}` - The display format of the time.
-/{abs|absolute}/{time}[.{ext}]
+- `{value}` - The time value to work with. Relative values can be specified by prefixing with `+` or `-`.
+  - Relative values are relative to the value acquired from the `now` parameter (which defaults to the current time).
+  - Whether the value is relative or absolute has nothing to do with the display format.
+  - `/absolute/+0` will display the current time in UTC.
+  - Note: The `now` parameter is returned in the `Date` response header.
+- `Accept` or `{.ext}` - Determines the output format. If not specified, `.svg` is assumed.
+  - `Accept` requires a valid MIME type.
+  - `.ext` requires a valid extension.
+  - Supported values: `.png`/`image/png`,
+- `X-Timezone` or `?tz={timezone}` - The timezone to display the time in. If not specified, UTC is assumed.
+- `?format={format}` - The format of the time to display. If not specified, `%Y-%m-%d %H:%M:%S` is assumed.
+  - Only relevant for `absolute` values.
+- `X-Date-Now` or `?now={timestamp}` - The timestamp to use for relative time calculations. If not specified, the current time is used.
+- `?static={boolean}` - Whether to redirect to a static version of the URL. Useful for creating specific URLs manually.
+  - If a value is not passed, (`?static`), `true` is assumed. Anything other than `true`, `1` or `yes` (case-insensitive) is considered `false`.
+  - Some header values will be translated to query parameters if provided (not `Accept`).
+  - e.g. `/rel/+3600.png?static&now=1752170474` will redirect to `/relative/1752174074.png`
+
+### Examples
+
+```
+/1752170474 => 2025-07-10 12:01:14 UTC
+/abs/1752170474 => 2025-07-10 12:01:14 UTC
+/absolute/+3600 => 2025-07-10 13:01:14 UTC
+/abs/-1800 => 2025-07-10 11:01:14 UTC
+/rel/1752170474 => 15 minutes ago
+/rel/+3600 => 1 hour from now
+/relative/-1800 => 30 minutes ago
+/relative/1752170474.png?tz=America/Chicago => 2025-07-10 06:01:14 CDT
+/relative/1752170474?type=relative => 2081-01-17 12:02:28 PM
 ```
 
-- If relative or absolute is not specified, it will be the opposite of the time string's format.
+## Ideas
+
+- Support for different timezone formats in query parameters or headers
+  - `?tz=...` or `X-Timezone: ...`
+  - `CST` or `America/Chicago` or `UTC-6` or `GMT-6` or `-0600`
+  - Automatically guessed based on geolocation of source IP address
+- Complex caching abilities
+  - Multi-level caching (disk, memory)
+  - Automatic expiry of relative items
+- `Accept` header support
+- IP-based rate limiting
+  - Multi-domain rate limiting factors
+    - Computational cost: 1ms = 1 token, max 100 tokens per minute
+    - Base rate: 3 requests per second
+- Cached Conversions
+  - If PNG is cached, then JPEG/WEBP/etc. can be converted from cached PNG
 
 ### Query Parameters