Connection.ping() implementation

.travis.yml

@@ -69,11 +69,11 @@ script:
   - docker-compose -f .travis/docker-compose.yml up -d
   - nvm ls-remote
   - npm install
-  #to permit benchmark with mariasql
-  - npm install mariasql
   - node --version
   - yarn --version
   - node .travis/wait-for-docker-up.js
   - if [ -n "$LINT" ] ; then yarn run test:lint; fi
   - if [ -z "$BENCH$LINT" ] ; then yarn run test:base; fi
+  # to permit benchmark with mariasql
+  - if [ -n "$BENCH" ] ; then npm install mariasql; fi
   - if [ -n "$BENCH" ] ; then yarn run benchmark; fi

documentation/readme.md

@@ -11,9 +11,9 @@ common API to mysql/mysql2:
 * `connect(callback)`: Connect event with callback
 * `changeUser(options, callback)`: change current connection user
 * `beginTransaction(options, callback)`: begin transaction
-* `commit(options, callback)`: commit current transaction
-* `rollback(options, callback)`: rollback current transaction
-* `ping(options, callback)`: send an empty packet to server to ensure connection
+* `commit(options, callback)`: commit current transaction if any
+* `rollback(options, callback)`: rollback current transaction if any
+* `ping(options, callback)`: send an empty packet to server to check that connection is active
 * `query(sql[, values][,callback])`: execute a [query](#query).
 * `pause()`: pause socket output.
 * `resume()`: resume socket output.
@@ -30,7 +30,7 @@ Not implemented :
 * `format(sql, value)`
 * `stats(options, callback)`
 
-escape function are not implemented, since it can lead to injection. 
+escape function are not intentionally implemented, since it can lead to injection. use Connection.query(sql, values), it will be more secure and faster
 statistic method is public in mysql, but not documented. 
 
 ### Initiate a connection
@@ -59,7 +59,7 @@ var conn3 = mariadb.createConnection({host: 'mydb.com', port:9999});
 ### Connection options
 
 
-#### important option 
+#### Important option 
 
 * `user`: string. user
 * `host`: string. IP or DNS of database server. default: 'localhost'
@@ -81,12 +81,13 @@ For those integer that are not in [safe](https://developer.mozilla.org/en-US/doc
 * `bigNumberStrings`: if integer is not in "safe" range, the value will be return as a string. 
 * `supportBigNumbers`: if integer is not in "safe" range, the value will be return as a [Long](https://www.npmjs.com/package/long) object.
 
-#### ssl
+#### Ssl
+
 //TODO describe all solutions
     
 * `ssl`: string/object. 
     
-#### other option 
+#### Other options 
 
 * `charset`: string. define charset exchange with server. default: UTF8MB4_UNICODE_CI
 * `dateStrings`: boolean.  indicate if date must be retrived as string (not as date). default: false

src/cmd/command.js

@@ -29,7 +29,7 @@ class Command extends EventEmitter {
 
   throwError(err) {
     if (this.onResult) {
-      this.onResult(err);
+      process.nextTick(this.onResult, err);
     } else {
       this.emit("error", err);
     }

src/cmd/ping.js

@@ -0,0 +1,63 @@
+"use strict";
+
+const Command = require("./command");
+const Utils = require("../misc/utils");
+
+/**
+ * send a COM_PING: permits sending a packet containing one byte to check that the connection is active.
+ * see https://mariadb.com/kb/en/library/com_ping/
+ */
+class Ping extends Command {
+  constructor(connEvents, onResult) {
+    super(connEvents);
+    this.onResult = onResult;
+  }
+
+  start(out, opts, info) {
+    out.startPacket(this);
+    out.writeInt8(0x0e);
+    out.flushBuffer(true);
+    return this.readPingResponsePacket;
+  }
+
+  /**
+   * Read ping response packet.
+   * packet can be :
+   * - an ERR_Packet
+   * - a OK_Packet
+   *
+   * @param packet  query response
+   * @param out     output writer
+   * @param opts    connection options
+   * @param info    connection info
+   * @returns {null}
+   */
+  readPingResponsePacket(packet, out, opts, info) {
+    switch (packet.peek()) {
+      //*********************************************************************************************************
+      //* OK response
+      //*********************************************************************************************************
+      case 0x00:
+        packet.skip(1); //skip header
+        info.status = packet.readUInt16();
+        if (this.onResult) process.nextTick(this.onResult, null);
+        this.emit("end");
+        return null;
+
+      //*********************************************************************************************************
+      //* ERROR response
+      //*********************************************************************************************************
+      case 0xff:
+        const err = packet.readError(info);
+        this.throwError(err);
+        return null;
+
+      default:
+        const errUnexpected = Utils.createError("unexpected packet", false, info);
+        this.throwError(errUnexpected);
+        return null;
+    }
+  }
+}
+
+module.exports = Ping;

src/cmd/resultset.js

@@ -188,11 +188,10 @@ class ResultSet extends Command {
         columns = this._columns;
       }
 
-      const self = this;
       if (columns) {
-        process.nextTick(() => self.onResult(null, rows, columns));
+        process.nextTick(this.onResult, null, rows, columns);
       } else {
-        process.nextTick(() => self.onResult(null, rows));
+        process.nextTick(this.onResult, null, rows);
       }
     }
 

src/connection.js

@@ -12,6 +12,7 @@ const tls = require("tls");
 /*commands*/
 const Handshake = require("./cmd/handshake/handshake");
 const Quit = require("./cmd/quit");
+const Ping = require("./cmd/ping");
 const Utils = require("./misc/utils");
 const Query = require("./cmd/query");
 
@@ -153,7 +154,8 @@ class Connection {
   }
 
   ping(options, callback) {
-    //TODO
+    const _cb = typeof options === "function" ? options : callback;
+    return this._addCommand(new Ping(this._events, _cb));
   }
 
   /**
@@ -205,7 +207,7 @@ class Connection {
             self._cmd.emit("error", err);
           }
         }
-        process.nextTick(() => self._socket.destroy());
+        process.nextTick(self._socket.destroy);
         killCon.end();
       });
     } else {
@@ -416,7 +418,7 @@ class Connection {
 
   _addCommandEnable(cmd) {
     let conn = this;
-    cmd.once("end", () => process.nextTick(() => conn._nextCmd()));
+    cmd.once("end", () => process.nextTick(conn._nextCmd.bind(conn)));
     if (!this._cmd && this._cmdQueue.isEmpty()) {
       this._cmd = cmd;
       this._cmd.init(this._out, this.opts, this.info);

test/integration/test-big-query.js

@@ -1,3 +1,5 @@
+"use strict";
+
 const base = require("../base.js");
 const assert = require("chai").assert;
 

test/integration/test-connection.js

@@ -3,7 +3,7 @@
 const base = require("../base.js");
 const assert = require("chai").assert;
 
-describe("connection event", () => {
+describe("connection", () => {
   it("multiple connect call", function(done) {
     const conn = base.createConnection();
     conn.connect(err => {
@@ -22,7 +22,7 @@ describe("connection event", () => {
     });
   });
 
-  it("event", function(done) {
+  it("connection event subscription", function(done) {
     let eventNumber = 0;
     const conn = base.createConnection();
     conn.on("connect", () => {
@@ -42,4 +42,12 @@ describe("connection event", () => {
     const query = conn.query("KILL CONNECTION_ID()");
     query.on("error", () => {});
   });
+
+  it("connection ping", function(done) {
+    shareConn.ping();
+    shareConn.ping(err => {
+      if (err) done(err);
+      done();
+    });
+  });
 });