document networking commands

pages/help.php

@@ -16,6 +16,7 @@
 <?php require __DIR__ . "/help/sgr_colors.php"; ?>
 <?php require __DIR__ . "/help/cmd_cursor.php"; ?>
 <?php require __DIR__ . "/help/cmd_screen.php"; ?>
+<?php require __DIR__ . "/help/cmd_d2d.php"; ?>
 <?php require __DIR__ . "/help/cmd_system.php"; ?>
 
 <script>

pages/help/cmd_d2d.php

@@ -0,0 +1,87 @@
+<div class="Box fold">
+	<h2>Commands: Networking</h2>
+
+	<div class="Row v">
+		<p>
+			ESPTerm implements commands for device-to-device messaging and for requesting external
+			servers. This can be used e.g. for remote control, status reporting or data upload / download.
+		</p>
+
+		<p>
+			Networking commands use the format `\e^...\a`, a Privacy Message (PM).
+			PM is similar to OSC, which uses `]` in place of `^`. The PM payload (text between `\e^` and `\a`)
+			must be shorter than 256 bytes,	and should not contain any control characters (ASCII < 32).
+		</p>
+
+		<h3>Device-to-device Messaging</h3>
+
+		<p>
+			To send a message to another ESPTerm module, use: `\e^M;<i>DestIP</i>;<i>message</i>\a`.
+		</p>
+
+		<p>
+			This command sends a POST request to `http://<i>&lt;DestIP&gt;</i>/api/v1/msg`.
+			The IP address may be appended by a port, if needed (eg. :8080).
+		</p>
+
+		<p>
+			Each ESPTerm listens for such requests and relays them to UART:
+			`\e^m;<i>SrcIP</i>;L=<i>length</i>;<i>message</i>\a`, with _length_ being the byte length of
+			_message_, as ASCII.
+		</p>
+
+		<p>
+			Notice a pattern with the first letter: capital is always a command, lower case a response.
+			This is followed with the HTTP commands and any networking commands added in the future.
+		</p>
+
+		<p>
+			*Example:* Node 192.168.0.10 sends a message to 192.168.0.19: `\e^M;192.168.0.19;Hello\a`.
+			Node 192.168.0.19 receives `\e^m;192.168.0.10;L=5;Hello\a` on the UART. Note that the IP
+			address in the reception message is that of the first node, thus it can be used to send a message back.
+		</p>
+
+		<h3>External HTTP requests</h3>
+
+		<p>
+			To request an external server, use `\e^H;<i>method</i>;<i>options</i>;<i>url</i>\n<i>body</i>\a`.
+		</p>
+
+		<ul>
+			<li>`_method_` - can be any usual HTTP verb, such as `GET`, `POST`, `PUT`, `HEAD`.
+			<li>`_options_` - is a comma-separated list of flags and parameters:
+				<ul>
+					<li>`H` - get response headers
+					<li>`B` - get response body
+					<li>`X` - ignore the response, return nothing
+					<li>`T=<i>ms</i>` - request timeout (default 5000~ms), in milliseconds
+					<li>`L=<i>bytes</i>` - limit response length (default 0 = don't limit). Applies to the head, body, or both combined, depending on the `H` and `B` flags
+					<li>`l=<i>bytes</i>` - limit the response buffer size (default 5000~B).
+						This can reduce RAM usage, however it shouldn't be set too small, as this buffer
+						is used for both headers and the response body.
+				</ul>
+			<li>`_url_` - full request URL, including `http://`. Port may be specified if different from :80,
+				and GET arguments may be appended to the URL if needed.
+			<li>`_body_` - optional, separated from `_url_` by a single line feed character (`\n`).
+				This can be used for POST and PUT requests. Note: the command may be truncated to the
+				maximum total length of 256 characters if too long.
+		</ul>
+
+		<p>The response has the following format: `\e^h;<i>status</i>;<i>options</i>;<i>response</i>\a`</p>
+
+		<ul>
+			<li>`_status_` - a HTTP status code, eg. 200 is OK, 404 Not found.
+			<li>`_options_` - similar to those in the request, here describing the response data.
+				This field can contain comma-separated `B`, `H` and `L=<i>bytes</i>`.
+			<li>`_response_` - the response, as requested. If both headers and body are received,
+				they will be separated by an empty line (i.e. `\r\n\r\n`). Response can be up to several
+				kilobytes long, depending on the `L=` and `l=` options.
+		</ul>
+
+		<p>
+			*Example:* `\e^H;GET;B;http://wtfismyip.com/text\a` - get the body of a web page
+			(wtfismyip.com is a service that sends back your IP address).
+			A response could be `\e^h;200;B,L=11;80.70.60.50\a`.
+		</p>
+	</div>
+</div>

pages/help/sgr_colors.php

@@ -1,6 +1,6 @@
 
 <div class="Box fold">
-	<h2>Commands: Color attributes</h2>
+	<h2>Commands: Color Attributes</h2>
 
 	<div class="Row v">
 		<p>

pages/help/sgr_styles.php

@@ -1,5 +1,5 @@
 <div class="Box fold">
-	<h2>Commands: Style attributes</h2>
+	<h2>Commands: Style Attributes</h2>
 
 	<div class="Row v">
 		<p>