[dom4j-dev] Attribute Quoting & Escaping Patch

[Christian Niles]

I ran into a problem yesterday with Internet Explorer that others may 
be interested in. I've submitted a patch to workaround the issue via 
the sourceforge site.

The problem I was having was that IE doesn't resolve entities within 
event attributes properly, such as onclick. Instead, it sends the raw 
string to the interpreter which throws an error. XMLWriter always 
escapes quote characters, even though attriubtes are always written 
with double-quotes and single-quotes don't actually need to be escaped. 
Thus, any string literals in my event code caused IE to mess up.

Since it's really common to use string literals in these attributes to 
do mouse-overs and such, the patch changes XMLWriter to only escape the 
quote character used to write the attribute value. In addition, it adds 
a field to OutputFormat to control which quote-character is used when 
writing attributes.

best,
christian.
Index: OutputFormat.java
===================================================================
RCS file: /cvsroot/dom4j/dom4j/src/java/org/dom4j/io/OutputFormat.java,v
retrieving revision 1.9
diff -u -r1.9 OutputFormat.java
--- OutputFormat.java   20 May 2002 08:14:16 -0000      1.9
+++ OutputFormat.java   26 Nov 2003 14:32:47 -0000
@@ -53,6 +53,8 @@
     /** Controls when to output a line.separtor every so many tags in case of no 
lines and total text trimming.*/
     private int newLineAfterNTags = 0;  //zero means don't bother.
 
+       /** Quote character to use when writing attributes. */
+       private char attributeQuoteChar = '\"';
 
     /** Creates an <code>OutputFormat</code> with
       * no additional whitespace (indent or new lines) added.
@@ -309,6 +311,36 @@
     public void setNewLineAfterNTags(int tagCount){
         newLineAfterNTags = tagCount;
     }
+
+       public char getAttributeQuoteCharacter() {
+
+               return attributeQuoteChar;
+
+       }
+
+       /**
+        * Sets the character used to quote attribute values. The specified
+        * character must be a valid XML attribute quote character, otherwise an
+        * <code>IllegalArgumentException</code> will be thrown.
+        * 
+        * @param quoteChar The character to use when quoting attribute values.
+        * @throws IllegalArgumentException If the specified character is not a
+        *              valid XML attribute quote character.
+        */
+       public void setAttributeQuoteCharacter(char quoteChar) {
+
+               if (quoteChar == '\'' || quoteChar == '"') {
+               
+                       attributeQuoteChar = quoteChar;
+                       
+               } else {
+
+                       throw new IllegalArgumentException(
+                               "Invalid attribute quote character (" + quoteChar + 
")");
+
+               }
+
+       }
 
     /** Parses command line arguments of the form
       * <code>-omitEncoding -indentSize 3 -newlines -trimText</code>
Index: XMLWriter.java
===================================================================
RCS file: /cvsroot/dom4j/dom4j/src/java/org/dom4j/io/XMLWriter.java,v
retrieving revision 1.62
diff -u -r1.62 XMLWriter.java
--- XMLWriter.java      14 Apr 2003 15:41:00 -0000      1.62
+++ XMLWriter.java      26 Nov 2003 14:32:48 -0000
@@ -1150,11 +1150,13 @@
                 }
             }
 
+                       char quote = format.getAttributeQuoteCharacter();
             writer.write(" ");
             writer.write(attribute.getQualifiedName());
-            writer.write("=\"");
+            writer.write("=");
+            writer.write(quote);
             writeEscapeAttributeEntities(attribute.getValue());
-            writer.write("\"");
+                       writer.write(quote);
         }
     }
 
@@ -1163,11 +1165,12 @@
         writer.write(attribute.getQualifiedName());
         writer.write("=");
 
-        writer.write("\"");
+               char quote = format.getAttributeQuoteCharacter();
+        writer.write(quote);
 
         writeEscapeAttributeEntities(attribute.getValue());
 
-        writer.write("\"");
+        writer.write(quote);
         lastOutputNodeType = Node.ATTRIBUTE_NODE;
     }
 
@@ -1178,11 +1181,13 @@
     }
 
     protected void writeAttribute(Attributes attributes, int index) throws 
IOException {
+               char quote = format.getAttributeQuoteCharacter();
         writer.write(" ");
         writer.write(attributes.getQName(index));
-        writer.write("=\"");
+        writer.write("=");
+        writer.write(quote);
         writeEscapeAttributeEntities(attributes.getValue(index));
-        writer.write("\"");
+        writer.write(quote);
     }
 
 
@@ -1336,6 +1341,8 @@
       * entity reference, suitable for XML attributes.
       */
     protected String escapeAttributeEntities(String text) {
+       char quote = format.getAttributeQuoteCharacter();
+       
         char[] block = null;
         int i, last = 0, size = text.length();
         for ( i = 0; i < size; i++ ) {
@@ -1349,9 +1356,14 @@
                     entity = "&gt;";
                     break;
                 case '\'' :
-                    entity = "&apos;";
+                       if (quote == '\'') {
+                           entity = "&apos;";
+                       }
                     break;
                 case '\"' :
+                                       if (quote == '\"') {
+                                               entity = "&quot;";
+                                       }
                     entity = "&quot;";
                     break;
                 case '&' :