Merge pull request #393 from /issues/324

add support for result rows as arrays

Author: brianc

lib/native/index.js

@@ -171,6 +171,10 @@ var clientBuilder = function(config) {
     connection._pulseQueryQueue(true);
   });
 
+  connection.on('_rowDescription', function(rowDescription) {
+    connection._activeQuery.handleRowDescription(rowDescription);
+  });
+
   //proxy some events to active query
   connection.on('_row', function(row) {
     connection._activeQuery.handleRow(row);

lib/native/query.js

@@ -16,12 +16,13 @@ var NativeQuery = function(config, values, callback) {
 
   var c = utils.normalizeQueryConfig(config, values, callback);
 
-	this.name = c.name;
+  this.name = c.name;
   this.text = c.text;
   this.values = c.values;
   this.callback = c.callback;
 
-  this._result = new Result();
+  this._result = new Result(config.rowMode);
+  this._addedFields = false;
   //normalize values
   if(this.values) {
     for(var i = 0, len = this.values.length; i < len; i++) {
@@ -33,19 +34,12 @@ var NativeQuery = function(config, values, callback) {
 
 util.inherits(NativeQuery, EventEmitter);
 
-//maps from native rowdata into api compatible row object
-var mapRowData = function(row) {
-  var result = {};
-  for(var i = 0, len = row.length; i < len; i++) {
-    var item = row[i];
-    result[item.name] = item.value === null ? null :
-      types.getTypeParser(item.type, 'text')(item.value);
-  }
-  return result;
+NativeQuery.prototype.handleRowDescription = function(rowDescription) {
+  this._result.addFields(rowDescription);
 };
 
 NativeQuery.prototype.handleRow = function(rowData) {
-  var row = mapRowData(rowData);
+  var row = this._result.parseRow(rowData);
   if(this.callback) {
     this._result.addRow(row);
   }

lib/query.js

@@ -23,7 +23,7 @@ var Query = function(config, values, callback) {
   this.callback = config.callback;
   this._fieldNames = [];
   this._fieldConverters = [];
-  this._result = new Result();
+  this._result = new Result(config.rowMode);
   this.isPreparedStatement = false;
   this._canceledDueToError = false;
   EventEmitter.call(this);
@@ -55,36 +55,16 @@ var noParse = function(val) {
 //message with this query object
 //metadata used when parsing row results
 Query.prototype.handleRowDescription = function(msg) {
-  this._fieldNames = [];
-  this._fieldConverters = [];
-  var len = msg.fields.length;
-  for(var i = 0; i < len; i++) {
-    var field = msg.fields[i];
-    var format = field.format;
-    this._fieldNames[i] = field.name;
-    this._fieldConverters[i] = Types.getTypeParser(field.dataTypeID, format);
-    this._result.addField(field);
-  }
+  this._result.addFields(msg.fields);
 };
 
 Query.prototype.handleDataRow = function(msg) {
-  var self = this;
-  var row = {};
-  for(var i = 0; i < msg.fields.length; i++) {
-    var rawValue = msg.fields[i];
-    if(rawValue === null) {
-      //leave null values alone
-      row[self._fieldNames[i]] = null;
-    } else {
-      //convert value to javascript
-      row[self._fieldNames[i]] = self._fieldConverters[i](rawValue);
-    }
-  }
-  self.emit('row', row, self._result);
+  var row = this._result.parseRow(msg.fields);
+  this.emit('row', row, this._result);
 
   //if there is a callback collect rows
-  if(self.callback) {
-    self._result.addRow(row);
+  if(this.callback) {
+    this._result.addRow(row);
   }
 };
 

lib/result.js

@@ -1,12 +1,18 @@
+var types = require(__dirname + '/types/');
+
 //result object returned from query
 //in the 'end' event and also
 //passed as second argument to provided callback
-var Result = function() {
+var Result = function(rowMode) {
   this.command = null;
   this.rowCount = null;
   this.oid = null;
   this.rows = [];
   this.fields = [];
+  this._parsers = [];
+  if(rowMode == "array") {
+    this.parseRow = this._parseRowAsArray;
+  }
 };
 
 var matchRegexp = /([A-Za-z]+) ?(\d+ )?(\d+)?/;
@@ -34,13 +40,55 @@ Result.prototype.addCommandComplete = function(msg) {
   }
 };
 
+Result.prototype._parseRowAsArray = function(rowData) {
+  var row = [];
+  for(var i = 0, len = rowData.length; i < len; i++) {
+    var rawValue = rowData[i];
+    if(rawValue !== null) {
+      row.push(this._parsers[i](rawValue));
+    } else {
+      row.push(null);
+    }
+  }
+  return row;
+};
+
+//rowData is an array of text or binary values
+//this turns the row into a JavaScript object
+Result.prototype.parseRow = function(rowData) {
+  var row = {};
+  for(var i = 0, len = rowData.length; i < len; i++) {
+    var rawValue = rowData[i];
+    var field = this.fields[i];
+    var fieldType = field.dataTypeID;
+    var parsedValue = null;
+    if(rawValue !== null) {
+      parsedValue = this._parsers[i](rawValue);
+    }
+    var fieldName = field.name;
+    row[fieldName] = parsedValue;
+  }
+  return row;
+};
+
 Result.prototype.addRow = function(row) {
   this.rows.push(row);
 };
 
-//Add a field definition to the result
-Result.prototype.addField = function(field) {
-  this.fields.push(field);
+Result.prototype.addFields = function(fieldDescriptions) {
+  //clears field definitions
+  //multiple query statements in 1 action can result in multiple sets
+  //of rowDescriptions...eg: 'select NOW(); select 1::int;'
+  //you need to reset the fields
+  if(this.fields.length) {
+    this.fields = [];
+    this._parsers = [];
+  }
+  for(var i = 0; i < fieldDescriptions.length; i++) {
+    var desc = fieldDescriptions[i];
+    this.fields.push(desc);
+    this._parsers.push(types.getTypeParser(desc.dataTypeID, desc.format || 'text'));
+  }
 };
 
 module.exports = Result;

src/binding.cc

@@ -61,7 +61,7 @@ class Connection : public ObjectWrap {
     routine_symbol = NODE_PSYMBOL("routine");
     name_symbol = NODE_PSYMBOL("name");
     value_symbol = NODE_PSYMBOL("value");
-    type_symbol = NODE_PSYMBOL("type");
+    type_symbol = NODE_PSYMBOL("dataTypeID");
     channel_symbol = NODE_PSYMBOL("channel");
     payload_symbol = NODE_PSYMBOL("payload");
     command_symbol = NODE_PSYMBOL("command");
@@ -522,13 +522,41 @@ class Connection : public ObjectWrap {
     }
     return false;
   }
+
+  //maps the postgres tuple results to v8 objects
+  //and emits row events
+  //TODO look at emitting fewer events because the back & forth between
+  //javascript & c++ might introduce overhead (requires benchmarking)
+  void EmitRowDescription(const PGresult* result)
+  {
+    HandleScope scope;
+    Local<Array> row = Array::New();
+    int fieldCount = PQnfields(result);
+    for(int fieldNumber = 0; fieldNumber < fieldCount; fieldNumber++) {
+      Local<Object> field = Object::New();
+      //name of field
+      char* fieldName = PQfname(result, fieldNumber);
+      field->Set(name_symbol, String::New(fieldName));
+
+      //oid of type of field
+      int fieldType = PQftype(result, fieldNumber);
+      field->Set(type_symbol, Integer::New(fieldType));
+
+      row->Set(Integer::New(fieldNumber), field);
+    }
+
+    Handle<Value> e = (Handle<Value>)row;
+    Emit("_rowDescription", &e);
+  }
+
   bool HandleResult(PGresult* result)
   {
     TRACE("PQresultStatus");
     ExecStatusType status = PQresultStatus(result);
     switch(status) {
     case PGRES_TUPLES_OK:
       {
+        EmitRowDescription(result);
         HandleTuplesResult(result);
         EmitCommandMetaData(result);
         return true;
@@ -592,24 +620,14 @@ class Connection : public ObjectWrap {
       Local<Array> row = Array::New();
       int fieldCount = PQnfields(result);
       for(int fieldNumber = 0; fieldNumber < fieldCount; fieldNumber++) {
-        Local<Object> field = Object::New();
-        //name of field
-        char* fieldName = PQfname(result, fieldNumber);
-        field->Set(name_symbol, String::New(fieldName));
-
-        //oid of type of field
-        int fieldType = PQftype(result, fieldNumber);
-        field->Set(type_symbol, Integer::New(fieldType));
 
         //value of field
         if(PQgetisnull(result, rowNumber, fieldNumber)) {
-          field->Set(value_symbol, Null());
+          row->Set(Integer::New(fieldNumber), Null());
         } else {
           char* fieldValue = PQgetvalue(result, rowNumber, fieldNumber);
-          field->Set(value_symbol, String::New(fieldValue));
+          row->Set(Integer::New(fieldNumber), String::New(fieldValue));
         }
-
-        row->Set(Integer::New(fieldNumber), field);
       }
 
       Handle<Value> e = (Handle<Value>)row;

test/integration/client/results-as-array-tests.js

@@ -0,0 +1,33 @@
+var util = require('util');
+var helper = require('./test-helper');
+
+var Client = helper.Client;
+
+var conInfo = helper.config;
+
+test('returns results as array', function() {
+  var client = new Client(conInfo);
+  var checkRow = function(row) {
+    assert(util.isArray(row), 'row should be an array');
+    assert.equal(row.length, 4);
+    assert.equal(row[0].getFullYear(), new Date().getFullYear());
+    assert.strictEqual(row[1], 1);
+    assert.strictEqual(row[2], 'hai');
+    assert.strictEqual(row[3], null);
+  }
+  client.connect(assert.success(function() {
+    var config = {
+      text: 'SELECT NOW(), 1::int, $1::text, null',
+      values: ['hai'],
+      rowMode: 'array'
+    };
+    var query = client.query(config, assert.success(function(result) {
+      assert.equal(result.rows.length, 1);
+      checkRow(result.rows[0]);
+      client.end();
+    }));
+    assert.emits(query, 'row', function(row) {
+      checkRow(row);
+    });
+  }));
+});

test/integration/client/row-description-on-results-tests.js

@@ -0,0 +1,37 @@
+var helper = require('./test-helper');
+
+var Client = helper.Client;
+
+var conInfo = helper.config;
+
+var checkResult = function(result) {
+  assert(result.fields);
+  assert.equal(result.fields.length, 3);
+  var fields = result.fields;
+  assert.equal(fields[0].name, 'now');
+  assert.equal(fields[1].name, 'num');
+  assert.equal(fields[2].name, 'texty');
+  assert.equal(fields[0].dataTypeID, 1184);
+  assert.equal(fields[1].dataTypeID, 23);
+  assert.equal(fields[2].dataTypeID, 25);
+};
+
+test('row descriptions on result object', function() {
+  var client = new Client(conInfo);
+  client.connect(assert.success(function() {
+    client.query('SELECT NOW() as now, 1::int as num, $1::text as texty', ["hello"], assert.success(function(result) {
+      checkResult(result);
+      client.end();
+    }));
+  }));
+});
+
+test('row description on no rows', function() {
+  var client = new Client(conInfo);
+  client.connect(assert.success(function() {
+    client.query('SELECT NOW() as now, 1::int as num, $1::text as texty LIMIT 0', ["hello"], assert.success(function(result) {
+      checkResult(result);
+      client.end();
+    }));
+  }));
+});