check free space before uploads and compare against local file

pi_finder/src/ssh.js

@@ -1,6 +1,7 @@
 var SSH = require('ssh2'),
     events = require('events'),
     path = require('path'),
+    fs = require('fs'),
     util = require('util');
 
 /**** ssh is an event emitter ****/
@@ -43,7 +44,7 @@ proto.password = 'raspberry';
 proto.host = '10.0.1.1';
 proto.port = 22;
 proto.type = 'shell';
-proto.install_command = 'curl -SLs http://bootstrap.uniontownlabs.org/install | sudo bash';
+proto.install_command = 'curl -SLs https://apt.adafruit.com/install | sudo bash';
 proto.pi_config = {};
 
 proto.handleError = function(err) {
@@ -105,31 +106,83 @@ proto.shutdown = function() {
 
 proto.upload = function() {
 
+  if(! this.file_upload || ! fs.existsSync(this.file_upload)) {
+    return this.handleError('no file specified');
+  }
+
+  var size = parseInt(fs.statSync(this.file_upload).size / 1000);
+
+  this.free(function(err, available) {
+
+    if(! available) {
+      return this.handleError(err || 'there is not enough space available to upload the selected file');
+    }
+
+    if(available <= size) {
+      return this.handleError('there is not enough space available to upload the selected file');
+    }
+
+    this.send_file();
+
+  }.bind(this));
+
+};
+
+proto.send_file = function() {
+
+  var self = this;
+
   this.ssh.sftp(function(err, sftp) {
 
     if(err) {
-      return this.handleError(err);
+      return self.handleError(err);
     }
 
-    var dest = '/home/' + this.username + '/' + path.basename(this.file_upload);
+    var dest = '/home/' + self.username + '/' + path.basename(self.file_upload);
 
     var progress = function(uploaded, chunk, total) {
       var percent = ((uploaded / total) * 100).toFixed(2);
-      this.handleData('\x1bc');
-      this.handleData(percent + '% complete\n');
-    }.bind(this);
+      self.handleData('\x1bc');
+      self.handleData(percent + '% complete\n');
+    };
 
-    sftp.fastPut(this.file_upload, dest, { step: progress }, function(err) {
+    sftp.fastPut(self.file_upload, dest, { step: progress }, function(err) {
 
       if(err) {
-        return this.handleError(err);
+        return self.handleError(err);
       }
 
-      this.emit('uploaded');
+      self.emit('uploaded');
 
-    }.bind(this));
+    });
 
-  }.bind(this));
+  });
+
+};
+
+proto.free = function(cb) {
+
+  this.ssh.exec('df /home | tail -1 | tr -s " " | cut -f 4 -d " "', function(err, stream) {
+
+    var data = '';
+
+    if(err) {
+      return cb(err);
+    }
+
+    stream.on('exit', function(code, signal) {
+
+      if(code) {
+        return cb('unable to calculate the free space available');
+      }
+
+      cb(null, parseInt(data) || 0);
+
+    }).on('data', function(d) {
+      data += d;
+    });
+
+  });
 
 };