repl: add history support for REPL

doc/api/repl.markdown

@@ -21,6 +21,10 @@ dropped into the REPL. It has simplistic emacs line-editing.
     2
     3
 
+By default, it will save your history to `~/.node_history`. To specify a
+different path, start node with the environment variable 
+`NODE_HISTORY_PATH=<the new history path>`.
+
 For advanced line-editors, start node with the environmental variable
 `NODE_NO_READLINE=1`. This will start the main and debugger REPL in canonical
 terminal settings which will allow you to use with `rlwrap`.
@@ -63,6 +67,9 @@ the following values:
  - `writer` - the function to invoke for each command that gets evaluated which
    returns the formatting (including coloring) to display. Defaults to
    `util.inspect`.
+
+- `useHistory` - a boolean which specifies whether or not to save the history
+   of the current session. Defaults to `false`.
 
 You can use your own `eval` function if it has following signature:
 

lib/repl.js

@@ -56,10 +56,22 @@ exports._builtinLibs = ['assert', 'buffer', 'child_process', 'cluster',
   'string_decoder', 'tls', 'tty', 'url', 'util', 'v8', 'vm', 'zlib',
   'smalloc'];
 
-
-function REPLServer(prompt, stream, eval_, useGlobal, ignoreUndefined) {
+var historyPath = path.join(process.env.HOME || process.env.USERPROFILE,
+                            '.node_history');
+
+function REPLServer(prompt,
+                    stream,
+                    eval_,
+                    useGlobal,
+                    ignoreUndefined,
+                    useHistory) {
   if (!(this instanceof REPLServer)) {
-    return new REPLServer(prompt, stream, eval_, useGlobal, ignoreUndefined);
+    return new REPLServer(prompt,
+                          stream,
+                          eval_,
+                          useGlobal,
+                          ignoreUndefined,
+                          useHistory);
   }
 
   var options, input, output, dom;
@@ -74,6 +86,7 @@ function REPLServer(prompt, stream, eval_, useGlobal, ignoreUndefined) {
     ignoreUndefined = options.ignoreUndefined;
     prompt = options.prompt;
     dom = options.domain;
+    useHistory = options.useHistory;
   } else if (!util.isString(prompt)) {
     throw new Error('An options Object, or a prompt String are required');
   } else {
@@ -86,7 +99,10 @@ function REPLServer(prompt, stream, eval_, useGlobal, ignoreUndefined) {
 
   self.useGlobal = !!useGlobal;
   self.ignoreUndefined = !!ignoreUndefined;
-
+  self.useHistory = !!useHistory;
+  if (self.useHistory) {
+    self.historyPath = process.env['NODE_HISTORY_PATH'] || historyPath;
+  }
   // just for backwards compat, see github.com/joyent/node/pull/7127
   self.rli = this;
 
@@ -197,6 +213,13 @@ function REPLServer(prompt, stream, eval_, useGlobal, ignoreUndefined) {
   self.setPrompt(self._prompt);
 
   self.on('close', function() {
+    if (self.useHistory) {
+      try {
+        fs.writeFileSync(self.historyPath, self.history.join('\n'), 'utf8');
+      }
+      // ignore errors
+      catch (err) {}
+    }
     self.emit('exit');
   });
 
@@ -309,6 +332,15 @@ function REPLServer(prompt, stream, eval_, useGlobal, ignoreUndefined) {
     self.displayPrompt(true);
   });
 
+  if (this.useHistory) {
+    try {
+      this.history = fs.readFileSync(self.historyPath, 'utf8').split('\n');
+      this.historyIndex = -1;
+    }
+    // ignore errors since we create on exit
+    catch (err) {}
+  }
+
   self.displayPrompt();
 }
 inherits(REPLServer, rl.Interface);
@@ -317,8 +349,18 @@ exports.REPLServer = REPLServer;
 
 // prompt is a string to print on each line for the prompt,
 // source is a stream to use for I/O, defaulting to stdin/stdout.
-exports.start = function(prompt, source, eval_, useGlobal, ignoreUndefined) {
-  var repl = new REPLServer(prompt, source, eval_, useGlobal, ignoreUndefined);
+exports.start = function(prompt,
+                         source,
+                         eval_,
+                         useGlobal,
+                         ignoreUndefined,
+                         useHistory) {
+  var repl = new REPLServer(prompt,
+                            source,
+                            eval_,
+                            useGlobal,
+                            ignoreUndefined,
+                            useHistory);
   if (!exports.repl) exports.repl = repl;
   return repl;
 };

src/node.js

@@ -119,14 +119,18 @@
         // REPL
         var opts = {
           useGlobal: true,
-          ignoreUndefined: false
+          ignoreUndefined: false,
+          useHistory: true
         };
         if (parseInt(process.env['NODE_NO_READLINE'], 10)) {
           opts.terminal = false;
         }
         if (parseInt(process.env['NODE_DISABLE_COLORS'], 10)) {
           opts.useColors = false;
         }
+        if (parseInt(process.env['NODE_DISABLE_HISTORY'], 10)) {
+          opts.useHistory = false;
+        }
         var repl = Module.requireRepl().start(opts);
         repl.on('exit', function() {
           process.exit();

test/parallel/test-repl-history.js

@@ -0,0 +1,58 @@
+var common = require('../common');
+var assert = require('assert');
+var Stream = require('stream');
+var repl = require('repl');
+var fs = require('fs');
+var path = require('path');
+
+process.env.NODE_HISTORY_PATH = path.join('..', 'fixtures', '.node_history');
+
+// create a dummy stream that does nothing
+var stream = new Stream();
+stream.write = stream.pause = stream.resume = function(){};
+stream.readable = stream.writable = true;
+
+function testTerminalMode() {
+  var r1 = repl.start({
+    terminal: true,
+    useHistory: true
+  });
+
+  process.stdin.write('blahblah');
+
+  process.nextTick(function() {
+    process.stdin.end();
+  });
+
+  r1.on('exit', function() {
+    console.log('r1 exit')
+    var contents = fs.readFileSync(process.env.NODE_HISTORY_PATH, 'utf8');
+    fs.unlinkSync(process.env.NODE_HISTORY_PATH);
+    assert.equal(contents, 'blahblah');
+    testRegularMode();
+  });
+}
+
+function testRegularMode() {
+  var r2 = repl.start({
+    input: stream,
+    output: stream,
+    terminal: false,
+    useHistory: true
+  });
+
+  stream.write('blahblah');
+
+  process.nextTick(function() {
+    stream.emit('end');
+  });
+
+  r2.on('exit', function() {
+    console.log('r2 exit')
+    var contents = fs.readFileSync(process.env.NODE_HISTORY_PATH, 'utf8');
+    fs.unlinkSync(process.env.NODE_HISTORY_PATH);
+    assert.equal(contents, 'blahblah');
+  });
+}
+
+testTerminalMode();

test/parallel/test-repl-options.js

@@ -25,6 +25,7 @@ assert.equal(r1.terminal, true);
 assert.equal(r1.useColors, r1.terminal);
 assert.equal(r1.useGlobal, false);
 assert.equal(r1.ignoreUndefined, false);
+assert.equal(r1.useHistory, false);
 
 // test r1 for backwards compact
 assert.equal(r1.rli.input, stream);

test/parallel/test-repl-timeout-throw.js

@@ -1,3 +1,4 @@
+process.env.NODE_DISABLE_HISTORY = 1;
 var assert = require('assert');
 var common = require('../common.js');
 

test/parallel/test-repl.js

@@ -258,7 +258,8 @@ function unix_test() {
       prompt: prompt_unix,
       input: socket,
       output: socket,
-      useGlobal: true
+      useGlobal: true,
+      useHistory: false
     }).context.message = message;
   });