Command history support

README.md

@@ -106,9 +106,12 @@ By integrating the loopback-console you also gain the ability to configure its f
 The following configuration directives are supported,
 
 - `quiet`: Suppresses the help text on startup and the automatic printing of `result`.
+- `historyPath`: The path to a file to persist command history. Use an empty string (`''`) to disable history.
 - All built-in configuration options for <a href="https://nodejs.org/api/repl.html" target="_blank">Node.js REPL</a>, such as `prompt`.
 - `handles`: Disable any default handles, or pass additional handles that you would like available on the console.
 
+Note, command history path can also be configured with the env-var `LOOPBACK_CONSOLE_HISTORY`.
+
 ## Contributors
 
 - Heath Morrison (<a href="https://github.com/doublemarked" target="_blank">doublemarked</a>)

history.js

@@ -0,0 +1,185 @@
+/*
+ * HM 2017-01-04:
+ * History processing was extracted from the internal Node REPL code with minimal changes,
+ *   https://github.com/nodejs/node/blob/master/lib/internal/repl.js
+ *
+ * This internal history functionality is currently unpublished for various reasons
+ * discussed in the following PR:
+ *   https://github.com/nodejs/node/pull/5789
+ *
+ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ *
+ * All extracted code remains under the general nodejs license terms:
+ *   https://github.com/nodejs/node/blob/master/LICENSE
+ *
+ *   Copyright Node.js contributors. All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ */
+
+'use strict';
+
+const Interface = require('readline').Interface;
+const path = require('path');
+const fs = require('fs');
+const os = require('os');
+const util = require('util');
+const debug = util.debuglog('repl');
+
+// XXX(chrisdickinson): The 15ms debounce value is somewhat arbitrary.
+// The debounce is to guard against code pasted into the REPL.
+const kDebounceHistoryMS = 15;
+
+const DEFAULT_HISTORY_FILE = '.loopback_console_history';
+
+module.exports = function initReplHistory(repl, historyPath) {
+  return new Promise((resolve, reject) => {
+    setupHistory(repl, historyPath, (err, repl) => {
+      if (err) {
+        reject(err);
+      } else {
+        resolve(repl);
+      }
+    });
+  });
+};
+
+function setupHistory(repl, historyPath, ready) {
+  // Empty string disables persistent history.
+  if (typeof historyPath === 'string')
+    historyPath = historyPath.trim();
+
+  if (historyPath === '') {
+    repl._historyPrev = _replHistoryMessage;
+    return ready(null, repl);
+  }
+
+  if (!historyPath) {
+    try {
+      historyPath = path.join(os.homedir(), DEFAULT_HISTORY_FILE);
+    } catch (err) {
+      repl._writeToOutput('\nError: Could not get the home directory.\n' +
+                          'REPL session history will not be persisted.\n');
+      repl._refreshLine();
+
+      debug(err.stack);
+      repl._historyPrev = _replHistoryMessage;
+      return ready(null, repl);
+    }
+  }
+
+  var timer = null;
+  var writing = false;
+  var pending = false;
+  repl.pause();
+  // History files are conventionally not readable by others:
+  // https://github.com/nodejs/node/issues/3392
+  // https://github.com/nodejs/node/pull/3394
+  fs.open(historyPath, 'a+', 0o0600, oninit);
+
+  function oninit(err, hnd) {
+    if (err) {
+      // Cannot open history file.
+      // Don't crash, just don't persist history.
+      repl._writeToOutput('\nError: Could not open history file.\n' +
+                          'REPL session history will not be persisted.\n');
+      repl._refreshLine();
+      debug(err.stack);
+
+      repl._historyPrev = _replHistoryMessage;
+      repl.resume();
+      return ready(null, repl);
+    }
+    fs.close(hnd, onclose);
+  }
+
+  function onclose(err) {
+    if (err) {
+      return ready(err);
+    }
+    fs.readFile(historyPath, 'utf8', onread);
+  }
+
+  function onread(err, data) {
+    if (err) {
+      return ready(err);
+    }
+
+    if (data) {
+      repl.history = data.split(/[\n\r]+/, repl.historySize);
+    }
+
+    fs.open(historyPath, 'w', onhandle);
+  }
+
+  function onhandle(err, hnd) {
+    if (err) {
+      return ready(err);
+    }
+    repl._historyHandle = hnd;
+    repl.on('line', online);
+
+    // reading the file data out erases it
+    repl.once('flushHistory', function() {
+      repl.resume();
+      ready(null, repl);
+    });
+    flushHistory();
+  }
+
+  // ------ history listeners ------
+  function online() {
+    repl._flushing = true;
+
+    if (timer) {
+      clearTimeout(timer);
+    }
+
+    timer = setTimeout(flushHistory, kDebounceHistoryMS);
+  }
+
+  function flushHistory() {
+    timer = null;
+    if (writing) {
+      pending = true;
+      return;
+    }
+    writing = true;
+    const historyData = repl.history.join(os.EOL);
+    fs.write(repl._historyHandle, historyData, 0, 'utf8', onwritten);
+  }
+
+  function onwritten(err, data) {
+    writing = false;
+    if (pending) {
+      pending = false;
+      online();
+    } else {
+      repl._flushing = Boolean(timer);
+      if (!repl._flushing) {
+        repl.emit('flushHistory');
+      }
+    }
+  }
+};
+
+function _replHistoryMessage() {
+  if (this.history.length === 0) {
+    this._writeToOutput(
+        '\nPersistent history support disabled. ' +
+        'Set the history path to ' +
+        'a valid, user-writable path to enable.\n'
+    );
+    this._refreshLine();
+  }
+  this._historyPrev = Interface.prototype._historyPrev;
+  return this._historyPrev();
+}

index.js

@@ -7,6 +7,7 @@ const DEFAULT_REPL_CONFIG = {
   prompt: 'loopback > ',
   useGlobal: true,
   ignoreUndefined: true,
+  historyPath: process.env.LOOPBACK_CONSOLE_HISTORY,
 };
 
 const DEFAULT_HANDLE_INFO = {
@@ -24,7 +25,7 @@ const LoopbackConsole = module.exports = {
 
   start(app, config) {
     if (this._started) {
-      return this._ctx;
+      return Promise.resolve(this._ctx);
     }
     this._started = true;
 
@@ -58,9 +59,10 @@ const LoopbackConsole = module.exports = {
       console.log(repl.usage(ctx));
     }
 
-    ctx.repl = repl.start(ctx);
-
-    return ctx;
+    return repl.start(ctx).then(repl => {
+      ctx.repl = repl;
+      return ctx;
+    });
   },
 
 };

package.json

@@ -1,6 +1,6 @@
 {
   "name": "loopback-console",
-  "version": "1.0.0",
+  "version": "1.1.0",
   "description": "A command-line tool for Loopback app debugging and administration",
   "main": "index.js",
   "license": "MIT",

repl.js

@@ -1,6 +1,7 @@
 'use strict';
 
 const repl = require('repl');
+const replHistory = require('./history');
 
 const LoopbackRepl = module.exports = {
   start(ctx) {
@@ -9,7 +10,6 @@ const LoopbackRepl = module.exports = {
 
     Object.assign(replServer.context, ctx.handles);
 
-    replServer.on('exit', process.exit);
     replServer.eval = wrapReplEval(replServer);
 
     if (ctx.handles.cb === true) {
@@ -43,7 +43,17 @@ const LoopbackRepl = module.exports = {
       },
     });
 
-    return replServer;
+    replServer.on('exit', function() {
+      if (replServer._flushing) {
+        replServer.pause();
+        return replServer.once('flushHistory', function() {
+          process.exit();
+        });
+      }
+      process.exit();
+    });
+
+    return replHistory(replServer, config.historyPath).then(() => replServer);
   },
 
   usage(ctx, details) {