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Merge pull request #2070 from evhan55/extensions/ev3-rate-limiting

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Add RateLimiter to EV3
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Evelyn Eastmond 2019-06-04 17:12:59 -04:00 committed by GitHub
commit 6c2d5b8a83
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1 changed files with 23 additions and 4 deletions
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27
src/extensions/scratch3_ev3/index.js
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@ -6,6 +6,7 @@ const uid = require('../../util/uid');
const BT = require('../../io/bt'); const BT = require('../../io/bt');
const Base64Util = require('../../util/base64-util'); const Base64Util = require('../../util/base64-util');
const MathUtil = require('../../util/math-util'); const MathUtil = require('../../util/math-util');
const RateLimiter = require('../../util/rateLimiter.js');
const log = require('../../util/log'); const log = require('../../util/log');
/** /**
@ -21,6 +22,12 @@ const blockIconURI = 'data:image/svg+xml;base64,PD94bWwgdmVyc2lvbj0iMS4wIiBlbmNv
*/ */
const Ev3PairingPin = '1234'; const Ev3PairingPin = '1234';
/**
* A maximum number of BT message sends per second, to be enforced by the rate limiter.
* @type {number}
*/
const BTSendRateMax = 40;
/** /**
* Enum for Ev3 direct command types. * Enum for Ev3 direct command types.
* Found in the 'EV3 Communication Developer Kit', section 4, page 24, at * Found in the 'EV3 Communication Developer Kit', section 4, page 24, at
@ -363,7 +370,7 @@ class EV3Motor {
] ]
); );
this._parent.send(cmd); this._parent.send(cmd, false); // don't use rate limiter to ensure motor stops
} }
/** /**
@ -482,6 +489,14 @@ class EV3 {
this._bt = null; this._bt = null;
this._runtime.registerPeripheralExtension(extensionId, this); this._runtime.registerPeripheralExtension(extensionId, this);
/**
* A rate limiter utility, to help limit the rate at which we send BT messages
* over the socket to Scratch Link to a maximum number of sends per second.
* @type {RateLimiter}
* @private
*/
this._rateLimiter = new RateLimiter(BTSendRateMax);
this.disconnect = this.disconnect.bind(this); this.disconnect = this.disconnect.bind(this);
this._onConnect = this._onConnect.bind(this); this._onConnect = this._onConnect.bind(this);
this._onMessage = this._onMessage.bind(this); this._onMessage = this._onMessage.bind(this);
@ -547,7 +562,7 @@ class EV3 {
] ]
); );
this.send(cmd); this.send(cmd, false); // don't use rate limiter to ensure sound stops
} }
stopAllMotors () { stopAllMotors () {
@ -609,12 +624,16 @@ class EV3 {
/** /**
* Send a message to the peripheral BT socket. * Send a message to the peripheral BT socket.
* @param {Uint8Array} message - the message to send. * @param {Uint8Array} message - the message to send.
* @param {boolean} [useLimiter=true] - if true, use the rate limiter
* @return {Promise} - a promise result of the send operation. * @return {Promise} - a promise result of the send operation.
*/ */
send (message) { send (message, useLimiter = true) {
// TODO: add rate limiting?
if (!this.isConnected()) return Promise.resolve(); if (!this.isConnected()) return Promise.resolve();
if (useLimiter) {
if (!this._rateLimiter.okayToSend()) return Promise.resolve();
}
return this._bt.sendMessage({ return this._bt.sendMessage({
message: Base64Util.uint8ArrayToBase64(message), message: Base64Util.uint8ArrayToBase64(message),
encoding: 'base64' encoding: 'base64'