Examples: add examples in C, Vala, JS, and Python on how to create and save documents

examples/c/Makefile

+CC=gcc
+CFLAGS=`pkg-config --cflags gxml gio-2.0` -g -Wall
+LDFLAGS=`pkg-config --libs gxml gio-2.0`
+
+example: example.o
+
+clean:
+	rm example *.o
+

examples/c/bookshelf.xml

+<?xml version="1.0"?>
+<Bookshelf>
+  <Owner fullname="John Green"/>
+  <Books>
+    <Book author="John Green" title="The Fault in Our Stars"/>
+    <Book author="Jane Austen" title="Pride &amp; Prejudice"/>
+    <Book author="J.D. Salinger" title="Nine Stories"/>
+  </Books>
+</Bookshelf>

examples/c/example.c

+#include <gxml/gxml.h>
+#include <stdio.h>
+
+int handle_error (GError *error) {
+  // TODO: better way to check whether it was set?
+  if (error != NULL) {
+    g_error (error->message);
+    return 1;
+  }
+
+  return 0;
+}
+
+int create_a_document () {
+  GError *error = NULL;
+  GXmlDocument *doc;
+  GXmlElement *root;
+  GXmlElement *owner;
+  GXmlElement *books;
+  GXmlElement *book;
+  int i;
+  char *str;
+
+  char *authors[] = { "John Green", "Jane Austen", "J.D. Salinger" };
+  char *titles[] = { "The Fault in Our Stars", "Pride & Prejudice", "Nine Stories" };
+
+  doc = gxml_document_new (&error);
+  handle_error (error);
+
+  // Add a root node
+  root = gxml_document_create_element (doc, "Bookshelf", &error);
+  handle_error (error);
+
+  gxml_dom_node_append_child (GXML_DOM_NODE (doc), GXML_DOM_NODE (root), &error);
+  handle_error (error);
+  // if we tried to add a second one, it would fail and GError would be set :)
+
+  // Add an owner node
+  owner = gxml_document_create_element (doc, "Owner", &error);
+  handle_error (error);
+  gxml_dom_node_append_child (GXML_DOM_NODE (root), GXML_DOM_NODE (owner), &error);
+  handle_error (error);
+  gxml_element_set_attribute (owner, "fullname", "John Green", &error);
+  // TODO: need to figure out what sort of errors these would return,
+  // want the devhelp pages to describe meaningful possible errors
+  handle_error (error);
+
+  // Add a collection of books
+  books = gxml_document_create_element (doc, "Books", &error);
+  handle_error (error);
+  gxml_dom_node_append_child (GXML_DOM_NODE (root), GXML_DOM_NODE (books), &error);
+
+  for (i = 0; i < sizeof (authors) / sizeof (char*); i++) {
+    book = gxml_document_create_element (doc, "Book", &error);
+    handle_error (error);
+    gxml_element_set_attribute (book, "author", authors[i], &error);
+    handle_error (error);
+    gxml_element_set_attribute (book, "title", titles[i], &error);
+    handle_error (error);
+    gxml_dom_node_append_child (GXML_DOM_NODE (books), GXML_DOM_NODE (book), &error);
+    handle_error (error);
+  }
+
+  // TODO: want a "gxml_dom_node_from_string ()"; make sure document ownership transfer properly
+
+  str = gxml_dom_node_to_string (GXML_DOM_NODE (doc), TRUE, 2);
+  printf ("create_a_document:\n%s\n", str);
+  g_free (str);
+
+  g_object_unref (doc); 
+  g_object_unref (root); // TODO: figure out what happens to root if you deallocate doc?! */
+  // TODO: perhaps see whether we can make it that all the nodes that are returned are weak references
+  g_object_unref (owner);
+  g_object_unref (books);
+  g_object_unref (book);
+  /* In util/ there's a small programme that tells you when ownership
+     is transfered (that is, you are given a return value that you own
+     and must free. */
+
+  return 0;
+}
+
+int create_a_document_minimal () {
+  GXmlDocument *doc;
+  GXmlElement *root;
+  GXmlElement *owner;
+  GXmlElement *books;
+  GXmlElement *book;
+  int i;
+  char *str;
+
+  char *authors[] = { "John Green", "Jane Austen", "J.D. Salinger" };
+  char *titles[] = { "The Fault in Our Stars", "Pride & Prejudice", "Nine Stories" };
+
+  doc = gxml_document_new (NULL);
+
+  // Add a root node
+  root = gxml_document_create_element (doc, "Bookshelf", NULL);
+  gxml_dom_node_append_child (GXML_DOM_NODE (doc), GXML_DOM_NODE (root), NULL);
+  // if we tried to add a second one, it would fail and GError would be set :)
+
+  // Add an owner node
+  owner = gxml_document_create_element (doc, "Owner", NULL);
+  gxml_dom_node_append_child (GXML_DOM_NODE (root), GXML_DOM_NODE (owner), NULL);
+  gxml_element_set_attribute (owner, "fullname", "John Green", NULL);
+  // TODO: need to figure out what sort of errors these would return,
+  // want the devhelp pages to describe meaningful possible errors
+
+  // Add a collection of books
+  books = gxml_document_create_element (doc, "Books", NULL);
+  gxml_dom_node_append_child (GXML_DOM_NODE (root), GXML_DOM_NODE (books), NULL);
+  for (i = 0; i < sizeof (authors) / sizeof (char*); i++) {
+    book = gxml_document_create_element (doc, "Book", NULL);
+    gxml_element_set_attribute (book, "author", authors[i], NULL);
+    gxml_element_set_attribute (book, "title", titles[i], NULL);
+    gxml_dom_node_append_child (GXML_DOM_NODE (books), GXML_DOM_NODE (book), NULL);
+  }
+
+  str = gxml_dom_node_to_string (GXML_DOM_NODE (doc), TRUE, 2);
+  printf ("create_a_document_minimal:\n%s\n", str);
+  g_free (str);
+
+  g_object_unref (doc);
+  g_object_unref (root);
+  g_object_unref (owner);
+  g_object_unref (books);
+  g_object_unref (book);
+
+  // TODO: how do we clean them up?
+
+  return 0;
+}
+
+int create_a_document_from_a_string () {
+  char *xml;
+  char *str;
+  GXmlDocument *doc;
+
+  xml = "<?xml version=\"1.0\"?><Bookshelf><Owner fullname=\"John Green\"/><Books><Book author=\"John Green\" title=\"The Fault in Our Stars\"/><Book author=\"Jane Austen\" title=\"Pride &amp; Prejudice\"/><Book author=\"J.D. Salinger\" title=\"Nine Stories\"/></Books></Bookshelf>";
+
+  doc = gxml_document_new_from_string (xml, NULL);
+
+  str = gxml_dom_node_to_string (GXML_DOM_NODE (doc), TRUE, 2);
+  printf ("create_a_document_from_a_string:\n%s\n", str);
+  g_free (str);
+
+  g_object_unref (doc);
+
+  return 0;
+}
+
+int create_a_document_from_a_file () {
+  GXmlDocument *doc;
+  GFile *file;
+  char *str;
+  GCancellable *can = g_cancellable_new ();
+  GError *error = NULL;
+
+  file = g_file_new_for_path ("bookshelf.xml");
+  doc = gxml_document_new_from_gfile (file, can, &error); // TODO: want to change this function name to "from file"
+  handle_error (error);
+
+  str = gxml_dom_node_to_string (GXML_DOM_NODE (doc), TRUE, 2);
+  printf ("create_a_document_from_a_file:\n%s\n", str);
+  g_free (str);
+
+  g_object_unref (doc);
+  // TODO: how do you free a GFile?  g_object_unref ()? 
+  
+
+  return 0;
+}
+
+int create_a_document_from_a_path () {
+  GXmlDocument *doc;
+  char *str;
+
+  doc = gxml_document_new_from_path ("bookshelf.xml", NULL); 
+  str = gxml_dom_node_to_string (GXML_DOM_NODE (doc), TRUE, 2);
+  printf ("create_a_document_from_a_file:\n%s\n", str);
+  g_free (str);
+
+  g_object_unref (doc);
+
+  return 0;
+}
+
+int saving_a_document_to_a_path () {
+  GXmlDocument *doc;
+
+  doc = gxml_document_new_from_path ("bookshelf.xml", NULL);
+
+  gxml_document_save_to_path (doc, "bookshelf2.xml");
+
+  g_object_unref (doc);
+
+  return 0;
+}
+
+int saving_a_document_to_a_stream () {
+  GXmlDocument *doc;
+  GFile *outfile;
+  GFileOutputStream *outstream;
+  GCancellable *can = g_cancellable_new ();
+  GError *error = NULL;
+
+  doc = gxml_document_new_from_path ("bookshelf.xml", &error);
+
+  outfile = g_file_new_for_path ("bookshelf3.xml");
+  outstream = g_file_replace (outfile, NULL, FALSE, G_FILE_CREATE_REPLACE_DESTINATION, can, &error);
+  gxml_document_save_to_stream (doc, G_OUTPUT_STREAM (outstream), can, &error);
+
+  g_object_unref (doc);
+  // TODO: figure out how to close/unref outstream and outfile
+
+  return 0;
+}
+
+int main (void) {
+  g_type_init ();
+
+  create_a_document (); // has token error checking
+  create_a_document_minimal ();
+  create_a_document_from_a_string ();
+  create_a_document_from_a_file ();
+  create_a_document_from_a_path ();
+  
+  saving_a_document_to_a_path ();
+  saving_a_document_to_a_stream ();
+
+  /* TODO: add these examples */
+  // find_nodes_of_given_tag ();
+  // find_nodes_matching_an_attribute ();
+
+  // accessing_attributes ();
+
+  // find_
+
+  return 0;
+}

examples/js/bookshelf.xml

+<?xml version="1.0"?>
+<Bookshelf>
+  <Owner fullname="John Green"/>
+  <Books>
+    <Book author="John Green" title="The Fault in Our Stars"/>
+    <Book author="Jane Austen" title="Pride &amp; Prejudice"/>
+    <Book author="J.D. Salinger" title="Nine Stories"/>
+  </Books>
+</Bookshelf>

examples/js/example.js

+#!/usr/bin/gjs
+
+const GXml = imports.gi.GXml;
+const Gio = imports.gi.Gio;
+
+function create_a_document () {
+    var authors = [ "John Green", "Jane Austen", "J.D. Salinger" ];
+    var titles = [ "The Fault in Our Stars", "Pride & Prejudice", "Nine Stories" ];
+
+    try {
+	let doc = GXml.Document.new ();
+	let root = doc.create_element ("Bookshelf");
+	doc.append_child (root);
+	let owner = doc.create_element ("Owner");
+	root.append_child (owner);
+	owner.set_attribute ("fullname", "John Green");
+
+	let books = doc.create_element ("Books");
+	root.append_child (books);
+
+	for (var i = 0; i < authors.length; i++) {
+	    let book = doc.create_element ("Book");
+	    book.set_attribute ("author", authors[i]);
+	    book.set_attribute ("title", titles[i]);
+	    books.append_child (book);
+	}
+
+	print ("create_a_document:\n" + doc.to_string (true, 4));
+    } catch (error) {
+	print (error.message);
+    }
+}
+
+function create_a_document_from_a_string () {
+    let xml = "<?xml version=\"1.0\"?>\
+<Bookshelf>\
+<Owner fullname=\"John Green\"/>\
+<Books>\
+<Book author=\"John Green\" title=\"The Fault in Our Stars\"/>\
+<Book author=\"Jane Austen\" title=\"Pride &amp; Prejudice\"/>\
+<Book author=\"J.D. Salinger\" title=\"Nine Stories\"/>\
+</Books>\
+</Bookshelf>";
+    let doc = GXml.Document.from_string (xml);
+    print ("create_a_document_from_a_string:\n" + doc.to_string (true, 4));
+    
+}
+
+function create_a_document_from_a_file () {
+    let file = Gio.File.new_for_path ("bookshelf.xml");
+    let can = new Gio.Cancellable ();
+    let doc = GXml.Document.from_gfile (file, can);
+    print ("create_a_document_from_a_file:\n" + doc.to_string (true, 4));
+}
+
+function create_a_document_from_a_path () {
+    let doc = GXml.Document.from_path ( "bookshelf.xml");
+    print ("create_a_document_from_a_path:\n" + doc.to_string (true, 4));
+}
+
+function saving_a_document_to_a_path () {
+    let doc = GXml.Document.from_path ("bookshelf.xml");
+    doc.save_to_path ("bookshelf2.xml");
+}
+
+create_a_document ();
+create_a_document_from_a_string ();
+create_a_document_from_a_file ();
+create_a_document_from_a_path ();
+saving_a_document_to_a_path ();

examples/python/bookshelf.xml

+<?xml version="1.0"?>
+<Bookshelf>
+  <Owner fullname="John Green"/>
+  <Books>
+    <Book author="John Green" title="The Fault in Our Stars"/>
+    <Book author="Jane Austen" title="Pride &amp; Prejudice"/>
+    <Book author="J.D. Salinger" title="Nine Stories"/>
+  </Books>
+</Bookshelf>

examples/python/example.py

+#!/usr/bin/python
+
+from gi.repository import GXml;
+from gi.repository import Gio;
+
+def create_a_document ():
+    authors = ["John Green", "Jane Austen", "J.D. Salinger"];
+    titles = ["The Fault in Our Stars", "Pride & Prejudice", "Nine Stories"];
+
+    doc = GXml.Document.new ();
+    root = doc.create_element ("Bookshelf");
+    doc.append_child (root);
+    root.set_attribute ("fullname", "John Green");
+    
+    books = doc.create_element ("Books");
+    root.append_child (books);
+    
+    for i in range (len (authors)):
+        book = doc.create_element ("Book");
+        book.set_attribute ("author", authors[i]);
+        book.set_attribute ("title", titles[i]);
+        books.append_child (book);
+    
+    print "create_a_document:\n", doc.to_string (True, 4);
+    if None == doc.to_string (True, 4):
+        print "ERROR: doc to string was null, but shouldn't be";
+
+def create_a_document_from_a_string ():
+    xml = """<?xml version="1.0"?>
+<Bookshelf>
+<Owner fullname="John Green"/>
+<Books>
+<Book author="John Green" title="The Fault in Our Stars"/>
+<Book author="Jane Austen" title="Pride &amp; Prejudice"/>
+<Book author="J.D. Salinger" title="Nine Stories"/>
+</Books>
+</Bookshelf>""";
+    doc = GXml.Document.from_string (xml);
+    print "create_a_document_from_a_string:\n", doc.to_string (True, 4);
+    # TODO: why does this not indent when printed?
+
+def create_a_document_from_a_file ():
+    can = Gio.Cancellable ();
+    gfile = Gio.File.new_for_path ("bookshelf.xml");
+    doc = GXml.Document.from_gfile (gfile, can);
+    print "create_a_document_from_a_file:\n", doc.to_string (True, 4); # TODO: do these two values actually do anything?
+
+def create_a_document_from_a_path ():
+    doc = GXml.Document.from_path ("bookshelf.xml");
+    print "create_a_document_from_a_path:\n", doc.to_string (True, 4); # TODO: do these two values actually do anything?
+
+def saving_a_document_to_a_path ():
+    doc = GXml.Document.from_path ("bookshelf.xml");
+    doc.save_to_path ("bookshelf2.xml");
+    
+
+create_a_document ();
+create_a_document_from_a_string ();
+create_a_document_from_a_file ();
+create_a_document_from_a_path ();
+saving_a_document_to_a_path ();
+

examples/vala/Makefile

+CC=valac
+CFLAGS=--vapidir=../../gxml --pkg gxml -o example
+
+example: example.vala
+	$(CC) $(CFLAGS) example.vala
+
+clean:
+	rm example
+

examples/vala/bookshelf.xml

+<?xml version="1.0"?>
+<Bookshelf>
+  <Owner fullname="John Green"/>
+  <Books>
+    <Book author="John Green" title="The Fault in Our Stars"/>
+    <Book author="Jane Austen" title="Pride &amp; Prejudice"/>
+    <Book author="J.D. Salinger" title="Nine Stories"/>
+  </Books>
+</Bookshelf>

examples/vala/example.vala

+using GXml;
+
+void create_a_document () {
+	string[] authors = { "John Green", "Jane Austen", "J.D. Salinger" };
+	string[] titles = { "The Fault in Our Stars", "Pride & Prejudice", "Nine Stories" };
+
+	try {
+		Document doc = new Document ();
+		Element root = doc.create_element ("Bookshelf");
+		doc.append_child (root);
+		Element owner = doc.create_element ("Owner");
+		root.append_child (owner);
+		owner.set_attribute ("fullname", "John Green");
+
+		Element books = doc.create_element ("Books");
+		root.append_child (books);
+
+		for (int i = 0; i < authors.length; i++) {
+			Element book = doc.create_element ("Book");
+			book.set_attribute ("author", authors[i]);
+			book.set_attribute ("title", titles[i]);
+			books.append_child (book);
+		}
+
+		stdout.printf ("create_a_document:\n%s\n", doc.to_string (true, 8));
+	} catch (GLib.Error e) {
+		stderr.printf ("%s\n", e.message);
+	}
+}
+
+void create_a_document_from_a_string () {
+	string xml;
+	Document doc;
+
+	xml = """<?xml version="1.0"?>
+<Bookshelf>
+<Owner fullname="John Green"/>
+<Books>
+<Book author="John Green" title="The Fault in Our Stars"/>
+<Book author="Jane Austen" title="Pride &amp; Prejudice"/>
+<Book author="J.D. Salinger" title="Nine Stories"/>
+</Books>
+</Bookshelf>""";
+
+	try {
+		doc = new Document.from_string (xml);
+		stdout.printf ("create_a_document_from_a_string:\n%s\n", doc.to_string (true, 8));
+	} catch (GXml.DomError e) {
+		stderr.printf ("%s\n", e.message);
+	}
+}
+
+void create_a_document_from_a_file () {
+	File f = File.new_for_path ("bookshelf.xml");
+	Cancellable can = new Cancellable ();
+	Document doc;
+
+	try {
+		doc = new Document.from_gfile (f, can);
+		stdout.printf ("create_a_document_from_a_file:\n%s\n", doc.to_string (true, 8));
+	} catch (DomError e) {
+		stderr.printf ("%s\n", e.message);
+	}
+}
+
+void create_a_document_from_a_path () {
+	Document doc;
+
+	try {
+		doc = new Document.from_path ("bookshelf.xml");
+		stdout.printf ("create_a_document_from_a_path:\n%s\n", doc.to_string (true, 8));
+	} catch (DomError e) {
+		stderr.printf ("%s\n", e.message);
+	}
+}
+
+void saving_a_document_to_a_path () {
+	Document doc;
+
+	try {
+		doc = new Document.from_path ("bookshelf.xml");
+		doc.save_to_path ("bookshelf2.xml");
+	} catch (DomError e) {
+		stderr.printf ("%s\n", e.message);
+	}
+}
+
+int main (string[] args) {
+	create_a_document ();
+	create_a_document_from_a_string ();
+	create_a_document_from_a_file ();
+	create_a_document_from_a_path ();
+	saving_a_document_to_a_path ();
+
+	return 0;
+}