genx

node-genx

node.js bindings to the Genx XML generation library.

Installing

npm install genx

Building From Source

There are a few ways to build this project:

• Running npm install in the node-genx root directory should automatically trigger a build. You should do this at least once regardless of which build method you wind up using since there are some necessary dependencies npm must install before compilation.
• If you have node-gyp installed, you can run node-gyp configure build
• If you have cmake 3.1 or higher and Node.js 0.10 or higher, you can build using cmake:

  mkdir -p build
  cd build
  cmake ..

• Scripts are included to automate this process. They also require the make command to be present:
  • Normal build: npm run-script clean && npm run-script cmake
  • Debug buildnpm run-script clean && npm run-script cmake-debug

Example

The following complete example uses Genx to reproduce the brief, single-entry Atom Feed Document in the Atom spec. The result is written to stdout.

var genx = require('genx');

// Passing "true" to the constructor indicates we want to nicely format the output
var w = new genx.Writer(true);

w.on('data', function(data) {
  process.stdout.write(data);
});

// Declare the elements and attributes up-front
var ns      = w.declareNamespace('http://www.w3.org/2005/Atom', '');
var feed    = w.declareElement(ns, 'feed');
var title   = w.declareElement(ns, 'title');
var link    = w.declareElement(ns, 'link');
var updated = w.declareElement(ns, 'updated');
var author  = w.declareElement(ns, 'author');
var name    = w.declareElement(ns, 'name');
var id      = w.declareElement(ns, 'id');
var entry   = w.declareElement(ns, 'entry');
var summary = w.declareElement(ns, 'summary');

var href    = w.declareAttribute('href');

// This is not a processing instruction and as such can't be generated by Genx
process.stdout.write("<?xml version=\"1.0\" encoding=\"utf-8\"?>\n");
w.startDocument()
  .startElement(feed)
    .startElement(title).addText("Example Feed").endElement()
    .startElement(link).addAttribute(href, "http://example.org/").endElement()
    .startElement(updated).addText("2003-12-13T18:30:02Z").endElement()
    .startElement(author)
      .startElement(name).addText("John Doe").endElement()
    .endElement()
    .startElement(id).addText("urn:uuid:60a76c80-d399-11d9-b93C-0003939e0af6").endElement()
    .startElement(entry)
      .startElement(title).addText("Atom-Powered Robots Run Amok").endElement()
      .startElement(link).addAttribute(href, "http://example.org/2003/12/13/atom03").endElementInline()
      .startElement(id).addText("urn:uuid:1225c695-cfb8-4ebb-aaaa-80da344efa6a").endElement()
      .startElement(updated).addText("2003-12-13T18:30:02Z").endElement()
      .startElement(summary).addText("Some text.").endElement()
    .endElement()
  .endElement()
.endDocument();

To run the above example:

node examples/atom.js

For more examples see, Generating XML With node.js.

API

The API pretty closely follows the underlying Genx library's API. This module exports one object, Writer, which you use to generate XML. Any errors encountered are raised as exceptions.

Note: Each of the following examples assumes the module has been imported and a Writer created as follows:

var genx = require('genx');
var writer = new genx.Writer();

Events

The Writer emits data events with a single string argument containing an XML fragment. You listen for data events in order to make use of the generated XML.

writer.on('data', function(data) {
  // Do something with the data such as write it to a file
});

For more information on how to use streams, consult the Node Streams API documentation.

Writer

The Writer class provides the primary interface to Genx. Call writer methods to generate XML. XML can be generated via literal nodes (elements, attributes) or by reusing pre-declared nodes. The Genx documentation claims that using predeclared nodes are more efficient. Where it makes sense the methods return this allowing calls to be chained. For example:

writer.startDocument().startElement(elem);

---

new Writer([prettyPrint], [newLine], [spacer])

Constructs a new Writer object.

Arguments

• prettyPrint (optional, boolean) -- Output human-readable / indented XML. Defaults to false
• newLine (optional, String) -- Character(s) to use as the newline character when prettyPrint is enabled. Defaults to \n
• spacer (optional, String) -- Character(s) to use to indent lines when prettyPrint is enabled. Defaults to \t

Return Value

Returns the created Writer

Example

// No output formatting
var writer = new genx.Writer();

// PrettyPrint with the default \n newlines and \t to indent
var writer = new genx.Writer(true);

// PrettyPrint with \r\n newlines and four spaces to indent
var writer = new genx.Writer(true, "\r\n", "    ");

---

startDocument()

Starts an XML document. Must be called before any elements can be added. This method may be called on a Writer multiple times after completing each document with endDocument in order to re-use a Writer and generate multiple documents.

Return Value

Returns the receiver.

Example

writer.startDocument();

---

endDocument()

Ends a document previously started with startDocument. Must be called after startDocument and after any open elements have been closed.

Return Value

Returns the receiver.

Example

writer.startDocument().endDocument();

---

declareNamespace(uri, [prefix])

Declares a namespace for later use in declareElement.

Arguments

• uri (mandatory, String) -- the uri of the namespace
• prefix (optional, String) -- the prefix that will be used for elements in this namespace. If the prefix is omitted Genx will generate one for you. Generated prefixes are of the form "gN", where N starts at 1. If prefix is the empty string, "", then this namespace will be set as the default namespace.

Return Value

Returns a Namespace object for later use with declareElement.

Examples

// Namespace with prefix
var ns = writer.declareNamespace('http://www.w3.org/2005/Atom', "atom");

// Default namespace
var ns = writer.declareNamespace('http://www.w3.org/2005/Atom', "");

// Generated prefix
var ns = writer.declareNamespace('http://www.w3.org/2005/Atom');

declareElement([namespace], name)

Declares an element with name name in namespace namespace. If no namespace is supplied then the element is in no namespace.

Arguments

• namespace (optional, Namespace) -- The namespace the element belongs to. Must be a Namespace object returned by declareNamespace.
• name (mandatory, String) -- The name of the element a.k.a. tag.

Return Value

Returns an Element object for later use with startElement.

Examples

// Element without a namespace
var elem = writer.declareElement('test');

// Namespaced element
var ns = writer.declareNamespace('http://www.w3.org/2005/Atom', "");
var elem = writer.declareElement(ns, 'feed');

---

declareAttribute([namespace], name)

Declares an attribute with name name in namespace namespace. If no namespace is supplied then the attribute is in no namespace.

Arguments

• namespace (optional, String) -- The namespace the attribute belongs to. Must be a Namespace object returned by declareNamespace.
• name (mandatory, String) -- The name of the attribute. The value is supplied later via addAttribute.

Return Value

Returns an Attribute object for later use with addAttribute.

Examples

// Attribute without a namespace
var elem = writer.declareElement('type');

// Namespaced attribute
var ns = writer.declareAttribute('http://www.w3.org/2005/Atom', "");
var elem = writer.declareAttribute(ns, 'type');

---

startElement(element)

Opens the element element.

Arguments

• element (mandatory, Element) -- The element to open. Must be an Element object previously declared via declareElement.

Return Value

Returns the receiver.

Example

var elem = writer.declareElement('feed');

writer.startDocument()
        .startElement(elem)
        .endElement()
      .endDocument()

---

startElementLiteral([namespace], name)

Opens an element with name, name in namespace namespace (a URI) without pre-declaring it. The Genx documentation claims that pre-declaring is more efficient, especially if the element is emitted multiple times.

Arguments

• namespace (optional, String) -- A namespace URI that the element belongs to. If a prefix for this namespace has previously been declared via declareNamespace then that prefix will be used, otherwise Genx will generate one of the form described in declareNamespace.
• name (mandatory, String) -- The name of the element to start.

Return Value

Returns the receiver.

Examples

// Without a namespace
writer.startDocument()
        .startElementLiteral('feed')
        .endElement()
      .endDocument()

// With a namespace
writer.startDocument()
        .startElementLiteral('http://www.w3.org/2005/Atom', 'feed')
        .endElement()
      .endDocument()

---

addText(text)

Adds a text node to the document.

Arguments

• text (mandatory, String) -- The text to add to the document.

Return Value

Returns the receiver.

Example

writer.startDocument()
        .startElementLiteral('feed')
          .addText("Some text")
        .endElement()
      .endDocument()

---

addComment(comment)

Arguments

• comment (mandatory, String) -- The comment text to add to the document.

Return Value

Returns the receiver.

Example

writer.startDocument()
        .addComment("Generated " + (new Date()).toString())
        .startElementLiteral('feed')
        .endElement()
      .endDocument();

---

addAttribute(attribute, value)

Arguments

• attribute (mandatory, Attribute) -- The attribute to add to the document. Must be an Attribute object previously declared via declareAttribute.
• value (mandatory, String) -- The attribute's value.

Return Value

Returns the receiver.

Example

var ns = writer.declareNamespace('http://www.w3.org/2005/Atom', '');
var feed = writer.declareElement(ns, 'feed');
var title = writer.declareElement(ns, 'title');
var type = writer.declareAttribute('type');

writer.startDocument()
        .startElement(feed)
          .startElement(title)
            .addAttribute(type, 'text')
            .addText("Test Title")
          .endElement()
        .endElement()
      .endDocument();

---

addAttributeLiteral([namespace], name, value)

Arguments

• namespace (optional, String) -- A namespace URI that the attribute belongs to. If a prefix for this namespace has previously been declared via declareNamespace then that prefix will be used, otherwise Genx will generate one of the form described in declareNamespace.
• name (mandatory, String) -- The attribute's name.
• value (mandatory, String) -- The attribute's value.

Return Value

Returns the receiver.

Example

var ns = writer.declareNamespace('http://www.w3.org/2005/Atom', '');
var feed = writer.declareElement(ns, 'feed');
var title = writer.declareElement(ns, 'title');

writer.startDocument()
        .startElement(feed)
          .startElement(title)
            .addAttributeLiteral('type', 'text')
            .addText("Test Title")
          .endElement()
        .endElement()
      .endDocument();

---

endElement()

Return Value

Returns the receiver.

Example

writer.startDocument()
        .startElementLiteral('feed')
        .endElement()
      .endDocument()

---

endElementInline()

Ends an element as an inline / "self-closing" tag. The element must only contain attributes, or an exception is thrown.

Return Value

Returns the receiver.

Example

writer.startDocument()
        .startElementLiteral('feed')
          .addAttributeLiteral('an-attribute', 'attribute-value')
        .endElementInline()
      .endDocument()

Running the Tests

This project has a test suite in the test directory. It utilises the Mocha test framework. To run the suite you need to have the mocha and should modules installed:

npm install -g mocha
npm install should

The suite is run by running mocha in the project root:

% mocha

  ...................................

  42 passing (23ms)

There is also a Guardfile present that enables automatically rebuilding the module and running the tests when one of the source files change. To use this you need the guard and guard-shell Ruby gems installed. This can be done as follows:

gem install guard guard-shell

Then run guard in the project root.

Contributors

• Morten Siebuhr -- https://github.com/msiebuhr
  • Applied fix for node-waf configuration errors on Linux
• Patrick Lavigne -- https://github.com/PMLavigne
  • Rewrote project to use Nan for compatibility with node 4+
  • Added PrettyPrint output
  • Merged in inline tags PR from jaydata

Changelog

• 1.2.2 -- 04 Jan 2016
  • "PrettyPrint" formatting
  • Inline Tags
  • Nan-based rewrite for node.js 4+ support
• 1.0.0 -- 17 Jan 2013
  • Update to support node 0.8.x
• 0.9.0 -- 31 Jan 2012
  • Update to support node 0.6.x
• 0.8.3 -- 22 Jun 2011
  • Fix build issues on Linux
• 0.8.2 -- 25 Feb 2011
  • Fix trailing comma in package.json