Merge pull request #269 from NoamGaash/feat/promisify

feat: promisify the "run" command

Author: Almenon

index.ts

@@ -309,10 +309,32 @@ export class PythonShell extends EventEmitter {
      * Runs a Python script and returns collected messages
      * @param  {string}   scriptPath   The path to the script to execute
      * @param  {Options}   options  The execution options
-     * @param  {Function} callback The callback function to invoke with the script results
-     * @return {PythonShell}       The PythonShell instance
+     * @param  {Function} (deprecated argument) callback The callback function to invoke with the script results
+     * @return {Promise<string[]> | PythonShell}  the output from the python script
      */
-    static run(scriptPath: string, options?: Options, callback?: (err?: PythonShellError, output?: any[]) => any) {
+     static run(scriptPath: string, options?: Options, callback?: (err?: PythonShellError, output?: any[]) => any) {
+
+        if(callback) {
+            console.warn('PythonShell.run() callback is deprecated. Use PythonShell.run() promise instead.')
+
+            return this.runLegacy(scriptPath, options, callback);
+        }
+        else {
+            return new Promise((resolve, reject) => {
+                let pyshell = new PythonShell(scriptPath, options);
+                let output = [];
+
+                pyshell.on('message', function (message) {
+                    output.push(message);
+                }).end(function (err) {
+                    if(err) reject(err);
+                    else resolve(output);
+                });
+            });
+        }
+    };
+
+    private static runLegacy(scriptPath: string, options?: Options, callback?: (err?: PythonShellError, output?: any[]) => any) {
         let pyshell = new PythonShell(scriptPath, options);
         let output = [];
 
@@ -323,14 +345,16 @@ export class PythonShell extends EventEmitter {
         });
     };
 
+
+
     /**
      * Runs the inputted string of python code and returns collected messages. DO NOT ALLOW UNTRUSTED USER INPUT HERE!
      * @param  {string}   code   The python code to execute
      * @param  {Options}   options  The execution options
      * @param  {Function} callback The callback function to invoke with the script results
      * @return {PythonShell}       The PythonShell instance
      */
-    static runString(code: string, options?: Options, callback?: (err: PythonShellError, output?: any[]) => any) {
+     static runString(code: string, options?: Options, callback?: (err: PythonShellError, output?: any[]) => any) {
 
         // put code in temp file
         const randomInt = getRandomInt();

package-lock.json

@@ -117,13 +117,20 @@ describe('PythonShell', function () {
         before(() => {
             PythonShell.defaultOptions = {};
         })
-        it('should be able to execute a string of python code', function (done) {
-            PythonShell.runString('print("hello");print("world")', null, function (err, results) {
+        it('should be able to execute a string of python code using callbacks', function (done) {
+            let pythonshell = PythonShell.runString('print("hello");print("world")', null, function (err, results) {
                 if (err) return done(err);
                 results.should.be.an.Array().and.have.lengthOf(2);
                 results.should.eql(['hello', 'world']);
                 done();
             });
+
+            pythonshell.should.be.an.instanceOf(PythonShell);
+        });
+        it('should be able to execute a string of python code using promises', async function () {
+            let results = await PythonShell.runString('print("hello");print("world")');
+            results.should.be.an.Array().and.have.lengthOf(2);
+            results.should.eql(['hello', 'world']);
         });
         after(() => {
             PythonShell.defaultOptions = {
@@ -134,7 +141,7 @@ describe('PythonShell', function () {
     });
 
     describe('#run(script, options)', function () {
-        it('should run the script and return output data', function (done) {
+        it('should run the script and return output data using callbacks', function (done) {
             PythonShell.run('echo_args.py', {
                 args: ['hello', 'world']
             }, function (err, results) {
@@ -144,13 +151,29 @@ describe('PythonShell', function () {
                 done();
             });
         });
+        it('should run the script and return output data using promise', async function () {
+            let results = await PythonShell.run('echo_args.py', {
+                args: ['hello', 'world']
+            });
+            results.should.be.an.Array().and.have.lengthOf(2);
+            results.should.eql(['hello', 'world']);
+        });
         it('should try to run the script and fail appropriately', function (done) {
             PythonShell.run('unknown_script.py', null, function (err, results) {
                 err.should.be.an.Error;
                 err.exitCode.should.be.exactly(2);
                 done();
             });
         });
+        it('should try to run the script and fail appropriately', async function () {
+            try {
+                let results = await PythonShell.run('unknown_script.py');
+                throw new Error(`should not get here because the script should fail` + results);
+            } catch (err) {
+                err.should.be.an.Error;
+                err.exitCode.should.be.exactly(2);
+            }
+        });
         it('should include both output and error', function (done) {
             PythonShell.run('echo_hi_then_error.py', null, function (err, results) {
                 err.should.be.an.Error;
@@ -250,8 +273,8 @@ describe('PythonShell', function () {
             };
         })
 
-        it('should run PythonShell normally without access to std streams', function (done) {
-            var pyshell = PythonShell.run('exit-code.py', {
+        it('should run PythonShell normally without access to std streams', async function () {
+            var pyshell = await PythonShell.run('exit-code.py', {
                 // 3 different ways of assigning values to the std streams in child_process.spawn()
                 // * ignore - pipe to /dev/null
                 // * inherit - inherit fd from parent process;
@@ -261,12 +284,10 @@ describe('PythonShell', function () {
                 // although the user shouldn't be doing this. We are just testing for
                 // increased code coverage
                 args: "0"
-            }, done);
+            });
 
-            should(pyshell.stdin).be.eql(null);
-            should(pyshell.stdout).be.eql(null);
-            should(pyshell.stderr).be.eql(null);
-            should.throws(() => { pyshell.send("asd") });
+            should(pyshell).be.eql([]);
+            
         });
     });