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[scpubgit/stemmaweb.git] / root / js / fileparse.js

// General-purpose error-handling function.
// TODO make sure this gets used throughout, where appropriate.
function display_error( jqXHR, el ) {
	var errmsg;
	if( jqXHR.responseText == "" ) {
		errmsg = "perhaps the server went down?"
	} else {
		var errobj;
		try {
			errobj = jQuery.parseJSON( jqXHR.responseText );
			errmsg = errobj.error;
		} catch ( parse_err ) {
			errmsg = "something went wrong on the server."
		}
	}
	var msghtml = $('<span>').attr('class', 'error').text( "An error occurred: " + errmsg );
	$(el).empty().append( msghtml ).show();
}

// Event to enable the upload button when a file has been selected
function file_selected( e ) {
	if( e.files.length == 1 ) {
		$('#upload_button').button('enable');
		$('#new_file_name_container').html( '<span id="new_file_name">' + e.files[0].name + '</span>' );
	} else {
		$('#upload_button').button('disable');
		$('#new_file_name_container').html( '(Use \'pick file\' to select a tradition file to upload.)' );
	}
}

// Implement our own AJAX method that uses the features of XMLHttpRequest2
// but try to let it have a similar interface to jquery.post
// The data var needs to be a FormData() object.
// The callback will be given a single argument, which is the response data
// of the given type.

function post_xhr2( url, data, cb, type ) {
	if( !type ) {
		type = 'json';
	}
	var xhr = new XMLHttpRequest();
	// Set the expected response type
	if( type === 'data' ) {
		xhr.responseType = 'blob';
	} else if( type === 'xml' ) {
		xhr.responseType = 'document';
	} 
	// Post the form
	// Gin up an AJAX settings object
	$.ajaxSetup({ url: url, type: 'POST' });
	xhr.open( 'POST', url, true );
	// Handle the results
	xhr.onload = function( e ) {
		// Get the response and parse it
		// Call the callback with the response, whatever it was
		var xhrs = e.target;
		if( xhrs.status > 199 && xhrs.status < 300  ) { // Success
			var resp;
			if( type === 'json' ) {
				resp = $.parseJSON( xhrs.responseText );
			} else if ( type === 'xml' ) {
				resp = xhrs.responseXML;
			} else if ( type === 'text' ) {
				resp = xhrs.responseText;
			} else {
				resp = xhrs.response;
			}
			cb( resp );
		} else {
			// Trigger the ajaxError...
			_trigger_ajaxerror( e );
		}
	};
	xhr.onerror = _trigger_ajaxerror;
	xhr.onabort = _trigger_ajaxerror;
	xhr.send( data );
}

function _trigger_ajaxerror( e ) {
	var xhr = e.target;
	var thrown = xhr.statusText || 'Request error';
	jQuery.event.trigger( 'ajaxError', [ xhr, $.ajaxSettings, thrown ]);
}

function upload_new () {
	// Serialize the upload form, get the file and attach it to the request,
	// POST the lot and handle the response.
	var newfile = $('#new_file').get(0).files[0];
	var reader = new FileReader();
	reader.onload = function( evt ) {
		var data = new FormData();
		$.each( $('#new_tradition').serializeArray(), function( i, o ) {
				data.append( o.name, o.value );
			});
		data.append( 'file', newfile );
		var upload_url = _get_url([ 'newtradition' ]);
		post_xhr2( upload_url, data, function( ret ) {
			if( ret.id ) {
				$('#upload-collation-dialog').dialog('close');
				refreshDirectory();
				loadTradition( ret.id, ret.name, 1 );
			} else if( ret.error ) {
				$('#upload_status').empty().append( 
					$('<span>').attr('class', 'error').append( ret.error ) );
			}
		}, 'json' );
	};
	reader.onerror = function( evt ) {
		var err_resp = 'File read error';
		if( e.name == 'NotFoundError' ) {
			err_resp = 'File not found';
		} else if ( e.name == 'NotReadableError' ) {
			err_resp == 'File unreadable - is it yours?';
		} else if ( e.name == 'EncodingError' ) {
			err_resp == 'File cannot be encoded - is it too long?';
		} else if ( e.name == 'SecurityError' ) {
			err_resp == 'File read security error';
		}
		// Fake a jqXHR object that we can pass to our generic error handler.
		var jqxhr = { responseText: '{error:"' + err_resp + '"}' };
		display_error( jqxhr, $('#upload_status') );
		$('#upload_button').button('disable');
	}
	
	reader.readAsBinaryString( newfile );
}

// Utility function to neatly construct an application URL
function _get_url( els ) {
	return basepath + els.join('/');
}

// TODO Attach unified ajaxError handler to document
$(document).ready( function() {
	// See if we have the browser functionality we need
	// TODO Also think of a test for SVG readiness
	if( !!window.FileReader && !!window.File ) {
		$('#compatibility_check').empty();
	}

	$('#upload-collation-dialog').dialog({
		autoOpen: false,
		height: 360,
		width: 480,
		modal: true,
		buttons: {
		  upload: {
		    text: 'Upload',
		    id: 'upload_button',
		    click: function() {
			    $('#upload_status').empty();
			    $('#upload_button').button("disable");
                upload_new();
            }
		  },
		  pick_file: {
		    text: 'Pick File',
		    id: 'pick_file_button',
		    click: function() {
                $('#new_file').click();
            }
		  },
		  Cancel: function() {
		    $('#upload-collation-dialog').dialog('close');
		  }
		},
		open: function() {
			// Set the upload button to its correct state based on
			// whether a file is loaded
			file_selected( $('#new_file').get(0) );
			$('#upload_status').empty();
		}
	}).ajaxError( function(event, jqXHR, ajaxSettings, thrownError) {
		// Reset button state
		file_selected( $('#new_file').get(0) );
		// Display error message if applicable
    	if( ajaxSettings.url.indexOf( 'newtradition' ) > -1 
    		&& ajaxSettings.type == 'POST' ) {
			display_error( jqXHR, $("#upload_status") );
    	}
	});;
	
});