std.xml
Warning: This module is considered out-dated and not up to Phobos' current standards. It will be removed from Phobos in 2.101.0. If you still need it, go to https://github.com/DigitalMars/undeaD
Classes and functions for creating and parsing XML
The basic architecture of this module is that there are standalone functions, classes for constructing an XML document from scratch (Tag, Element and Document), and also classes for parsing a pre-existing XML file (ElementParser and DocumentParser). The parsing classes may be used to build a Document, but that is not their primary purpose. The handling capabilities of DocumentParser and ElementParser are sufficiently customizable that you can make them do pretty much whatever you want.
- Example
- This example creates a DOM (Document Object Model) tree from an XML file.
import std.xml; import std.stdio; import std.string; import std.file; // books.xml is used in various samples throughout the Microsoft XML Core // Services (MSXML) SDK. // // See http://msdn2.microsoft.com/en-us/library/ms762271(VS.85).aspx void main() { string s = cast(string) std.file.read("books.xml"); // Check for well-formedness check(s); // Make a DOM tree auto doc = new Document(s); // Plain-print it writeln(doc); }
- Example
- This example does much the same thing, except that the file is deconstructed and reconstructed by hand. This is more work, but the techniques involved offer vastly more power.
import std.xml; import std.stdio; import std.string; struct Book { string id; string author; string title; string genre; string price; string pubDate; string description; } void main() { string s = cast(string) std.file.read("books.xml"); // Check for well-formedness check(s); // Take it apart Book[] books; auto xml = new DocumentParser(s); xml.onStartTag["book"] = (ElementParser xml) { Book book; book.id = xml.tag.attr["id"]; xml.onEndTag["author"] = (in Element e) { book.author = e.text(); }; xml.onEndTag["title"] = (in Element e) { book.title = e.text(); }; xml.onEndTag["genre"] = (in Element e) { book.genre = e.text(); }; xml.onEndTag["price"] = (in Element e) { book.price = e.text(); }; xml.onEndTag["publish-date"] = (in Element e) { book.pubDate = e.text(); }; xml.onEndTag["description"] = (in Element e) { book.description = e.text(); }; xml.parse(); books ~= book; }; xml.parse(); // Put it back together again; auto doc = new Document(new Tag("catalog")); foreach (book;books) { auto element = new Element("book"); element.tag.attr["id"] = book.id; element ~= new Element("author", book.author); element ~= new Element("title", book.title); element ~= new Element("genre", book.genre); element ~= new Element("price", book.price); element ~= new Element("publish-date",book.pubDate); element ~= new Element("description", book.description); doc ~= element; } // Pretty-print it writefln(join(doc.pretty(3),"\n")); }
- License:
- Boost License 1.0.
- Authors:
- Janice Caron
- Source
- std/xml.d
- pure nothrow @nogc @safe bool isChar(dchar c);
-
Returns true if the character is a character according to the XML standard
- Standards:
- XML 1.0
- Parameters:
dchar c
the character to be tested
- pure nothrow @nogc @safe bool isSpace(dchar c);
-
Returns true if the character is whitespace according to the XML standard
Only the following characters are considered whitespace in XML - space, tab, carriage return and linefeed
- Standards:
- XML 1.0
- Parameters:
dchar c
the character to be tested
- pure nothrow @nogc @safe bool isDigit(dchar c);
-
Returns true if the character is a digit according to the XML standard
- Standards:
- XML 1.0
- Parameters:
dchar c
the character to be tested
- pure nothrow @nogc @safe bool isLetter(dchar c);
-
Returns true if the character is a letter according to the XML standard
- Standards:
- XML 1.0
- Parameters:
dchar c
the character to be tested
- pure nothrow @nogc @safe bool isIdeographic(dchar c);
-
Returns true if the character is an ideographic character according to the XML standard
- Standards:
- XML 1.0
- Parameters:
dchar c
the character to be tested
- pure nothrow @nogc @safe bool isBaseChar(dchar c);
-
Returns true if the character is a base character according to the XML standard
- Standards:
- XML 1.0
- Parameters:
dchar c
the character to be tested
- pure nothrow @nogc @safe bool isCombiningChar(dchar c);
-
Returns true if the character is a combining character according to the XML standard
- Standards:
- XML 1.0
- Parameters:
dchar c
the character to be tested
- pure nothrow @nogc @safe bool isExtender(dchar c);
-
Returns true if the character is an extender according to the XML standard
- Standards:
- XML 1.0
- Parameters:
dchar c
the character to be tested
- S encode(S)(S s);
-
Encodes a string by replacing all characters which need to be escaped with appropriate predefined XML entities.
encode() escapes certain characters (ampersand, quote, apostrophe, less-than and greater-than), and similarly, decode() unescapes them. These functions are provided for convenience only. You do not need to use them when using the std.xml classes, because then all the encoding and decoding will be done for you automatically.
If the string is not modified, the original will be returned.- Standards:
- XML 1.0
- Parameters:
S s
The string to be encoded
- Returns:
- The encoded string
- Example
writefln(encode("a > b")); // writes "a > b"
- enum DecodeMode: int;
-
Mode to use for decoding.
- NONE
- LOOSE
- STRICT
- pure @safe string decode(string s, DecodeMode mode = DecodeMode.LOOSE);
-
Decodes a string by unescaping all predefined XML entities.
encode() escapes certain characters (ampersand, quote, apostrophe, less-than and greater-than), and similarly, decode() unescapes them. These functions are provided for convenience only. You do not need to use them when using the std.xml classes, because then all the encoding and decoding will be done for you automatically.
This function decodes the entities &, ", ', < and >, as well as decimal and hexadecimal entities such as €
If the string does not contain an ampersand, the original will be returned.
Note that the "mode" parameter can be one of DecodeMode.NONE (do not decode), DecodeMode.LOOSE (decode, but ignore errors), or DecodeMode.STRICT (decode, and throw a DecodeException in the event of an error).- Standards:
- XML 1.0
- Parameters:
string s
The string to be decoded DecodeMode mode
(optional) Mode to use for decoding. (Defaults to LOOSE).
- Throws:
- DecodeException if mode == DecodeMode.STRICT and decode fails
- Returns:
- The decoded string
- Example
writefln(decode("a > b")); // writes "a > b"
- class Document: std.xml.Element;
-
Class representing an XML document.
- Standards:
- XML 1.0
- string prolog;
-
Contains all text which occurs before the root element. Defaults to <?xml version="1.0"?>
- string epilog;
-
Contains all text which occurs after the root element. Defaults to the empty string
- this(string s);
-
Constructs a Document by parsing XML text.
This function creates a complete DOM (Document Object Model) tree.
The input to this function MUST be valid XML. This is enforced by DocumentParser's in contract.- Parameters:
string s
the complete XML text.
- this(const(Tag) tag);
-
Constructs a Document from a Tag.
- Parameters:
const(Tag) tag
the start tag of the document.
- const bool opEquals(scope const Object o);
-
Compares two Documents for equality
- Example
Document d1,d2; if (d1 == d2) { }
- const scope int opCmp(scope const Object o);
-
Compares two Documents
You should rarely need to call this function. It exists so that Documents can be used as associative array keys.
- Example
Document d1,d2; if (d1 < d2) { }
- const scope @trusted size_t toHash();
-
Returns the hash of a Document
You should rarely need to call this function. It exists so that Documents can be used as associative array keys.
- const scope @safe string toString();
-
Returns the string representation of a Document. (That is, the complete XML of a document).
- class Element: std.xml.Item;
-
Class representing an XML element.
- Standards:
- XML 1.0
- Tag tag;
-
The start tag of the element
- Item[] items;
-
The element's items
- Text[] texts;
-
The element's text items
- CData[] cdatas;
-
The element's CData items
- Comment[] comments;
-
The element's comments
- ProcessingInstruction[] pis;
-
The element's processing instructions
- Element[] elements;
-
The element's child elements
- pure @safe this(string name, string interior = null);
-
Constructs an Element given a name and a string to be used as a Text interior.
- Parameters:
string name
the name of the element. string interior
(optional) the string interior.
- Example
auto element = new Element("title","Serenity") // constructs the element <title>Serenity</title>
- pure @safe this(const(Tag) tag_);
-
Constructs an Element from a Tag.
- Parameters:
const(Tag) tag_
the start or empty tag of the element.
- pure @safe void opOpAssign(string op)(Text item)
Constraints: if (op == "~"); -
Append a text item to the interior of this element
- Parameters:
Text item
the item you wish to append.
- Example
Element element; element ~= new Text("hello");
- pure @safe void opOpAssign(string op)(CData item)
Constraints: if (op == "~"); -
Append a CData item to the interior of this element
- Parameters:
CData item
the item you wish to append.
- Example
Element element; element ~= new CData("hello");
- pure @safe void opOpAssign(string op)(Comment item)
Constraints: if (op == "~"); -
Append a comment to the interior of this element
- Parameters:
Comment item
the item you wish to append.
- Example
Element element; element ~= new Comment("hello");
- pure @safe void opOpAssign(string op)(ProcessingInstruction item)
Constraints: if (op == "~"); -
Append a processing instruction to the interior of this element
- Parameters:
ProcessingInstruction item
the item you wish to append.
- Example
Element element; element ~= new ProcessingInstruction("hello");
- pure @safe void opOpAssign(string op)(Element item)
Constraints: if (op == "~"); -
Append a complete element to the interior of this element
- Parameters:
Element item
the item you wish to append.
- Example
Element element; Element other = new Element("br"); element ~= other; // appends element representing <br />
- const bool opEquals(scope const Object o);
-
Compares two Elements for equality
- Example
Element e1,e2; if (e1 == e2) { }
- const @safe int opCmp(scope const Object o);
-
Compares two Elements
You should rarely need to call this function. It exists so that Elements can be used as associative array keys.
- Example
Element e1,e2; if (e1 < e2) { }
- const scope @safe size_t toHash();
-
Returns the hash of an Element
You should rarely need to call this function. It exists so that Elements can be used as associative array keys.
- const string text(DecodeMode mode = DecodeMode.LOOSE);
-
Returns the decoded interior of an element.
The element is assumed to contain text only. So, for example, given XML such as "<title>Good & Bad</title>", will return "Good & Bad".
- Parameters:
DecodeMode mode
(optional) Mode to use for decoding. (Defaults to LOOSE).
- Throws:
- DecodeException if decode fails
- const scope string[] pretty(uint indent = 2);
-
Returns an indented string representation of this item
- Parameters:
uint indent
(optional) number of spaces by which to indent this element. Defaults to 2.
- const scope @safe string toString();
-
Returns the string representation of an Element
- Example
auto element = new Element("br"); writefln(element.toString()); // writes "<br />"
- enum TagType: int;
-
Tag types.
- START
- END
- EMPTY
- class Tag;
-
Class representing an XML tag.
- Standards:
-
XML 1.0 The class invariant guarantees
- that type is a valid enum TagType value
- that name consists of valid characters
- that each attribute name consists of valid characters
- TagType type;
-
Type of tag
- string name;
-
Tag name
- string[string] attr;
-
Associative array of attributes
- pure @safe this(string name, TagType type = TagType.START);
-
Constructs an instance of Tag with a specified name and type
The constructor does not initialize the attributes. To initialize the attributes, you access the attr member variable.
- Parameters:
string name
the Tag's name TagType type
(optional) the Tag's type. If omitted, defaults to TagType.START.
- Example
auto tag = new Tag("img",Tag.EMPTY); tag.attr["src"] = "http://example.com/example.jpg";
- const bool opEquals(scope Object o);
-
Compares two Tags for equality
You should rarely need to call this function. It exists so that Tags can be used as associative array keys.
- Example
Tag tag1,tag2 if (tag1 == tag2) { }
- const int opCmp(Object o);
-
Compares two Tags
- Example
Tag tag1,tag2 if (tag1 < tag2) { }
- const size_t toHash();
-
Returns the hash of a Tag
You should rarely need to call this function. It exists so that Tags can be used as associative array keys.
- const @safe string toString();
-
Returns the string representation of a Tag
- Example
auto tag = new Tag("book",TagType.START); writefln(tag.toString()); // writes "<book>"
- const pure nothrow @nogc @property @safe bool isStart();
-
Returns true if the Tag is a start tag
- Example
if (tag.isStart) { }
- const pure nothrow @nogc @property @safe bool isEnd();
-
Returns true if the Tag is an end tag
- Example
if (tag.isEnd) { }
- const pure nothrow @nogc @property @safe bool isEmpty();
-
Returns true if the Tag is an empty tag
- Example
if (tag.isEmpty) { }
- class Comment: std.xml.Item;
-
Class representing a comment
- pure @safe this(string content);
-
Construct a comment
- Parameters:
string content
the body of the comment
- Throws:
- CommentException if the comment body is illegal (contains "--" or exactly equals "-")
- Example
auto item = new Comment("This is a comment"); // constructs <!--This is a comment-->
- const bool opEquals(scope const Object o);
-
Compares two comments for equality
- Example
Comment item1,item2; if (item1 == item2) { }
- const scope int opCmp(scope const Object o);
-
Compares two comments
You should rarely need to call this function. It exists so that Comments can be used as associative array keys.
- Example
Comment item1,item2; if (item1 < item2) { }
- const nothrow scope size_t toHash();
-
Returns the hash of a Comment
You should rarely need to call this function. It exists so that Comments can be used as associative array keys.
- const pure nothrow scope @safe string toString();
-
Returns a string representation of this comment
- const pure nothrow @nogc @property scope @safe bool isEmptyXML();
-
Returns false always
- class CData: std.xml.Item;
-
Class representing a Character Data section
- pure @safe this(string content);
-
Construct a character data section
- Parameters:
string content
the body of the character data segment
- Throws:
- CDataException if the segment body is illegal (contains "]]>")
- Example
auto item = new CData("<b>hello</b>"); // constructs <![CDATA[<b>hello</b>]]>
- const bool opEquals(scope const Object o);
-
Compares two CDatas for equality
- Example
CData item1,item2; if (item1 == item2) { }
- const scope int opCmp(scope const Object o);
-
Compares two CDatas
You should rarely need to call this function. It exists so that CDatas can be used as associative array keys.
- Example
CData item1,item2; if (item1 < item2) { }
- const nothrow scope size_t toHash();
-
Returns the hash of a CData
You should rarely need to call this function. It exists so that CDatas can be used as associative array keys.
- const pure nothrow scope @safe string toString();
-
Returns a string representation of this CData section
- const pure nothrow @nogc @property scope @safe bool isEmptyXML();
-
Returns false always
- class Text: std.xml.Item;
-
Class representing a text (aka Parsed Character Data) section
- pure @safe this(string content);
-
Construct a text (aka PCData) section
- Parameters:
string content
the text. This function encodes the text before insertion, so it is safe to insert any text
- Example
auto Text = new CData("a < b"); // constructs a < b
- const bool opEquals(scope const Object o);
-
Compares two text sections for equality
- Example
Text item1,item2; if (item1 == item2) { }
- const scope int opCmp(scope const Object o);
-
Compares two text sections
You should rarely need to call this function. It exists so that Texts can be used as associative array keys.
- Example
Text item1,item2; if (item1 < item2) { }
- const nothrow scope size_t toHash();
-
Returns the hash of a text section
You should rarely need to call this function. It exists so that Texts can be used as associative array keys.
- const pure nothrow @nogc scope @safe string toString();
-
Returns a string representation of this Text section
- const pure nothrow @nogc @property scope @safe bool isEmptyXML();
-
Returns true if the content is the empty string
- class XMLInstruction: std.xml.Item;
-
Class representing an XML Instruction section
- pure @safe this(string content);
-
Construct an XML Instruction section
- Parameters:
string content
the body of the instruction segment
- Throws:
- XIException if the segment body is illegal (contains ">")
- Example
auto item = new XMLInstruction("ATTLIST"); // constructs <!ATTLIST>
- const bool opEquals(scope const Object o);
-
Compares two XML instructions for equality
- Example
XMLInstruction item1,item2; if (item1 == item2) { }
- const scope int opCmp(scope const Object o);
-
Compares two XML instructions
You should rarely need to call this function. It exists so that XmlInstructions can be used as associative array keys.
- Example
XMLInstruction item1,item2; if (item1 < item2) { }
- const nothrow scope size_t toHash();
-
Returns the hash of an XMLInstruction
You should rarely need to call this function. It exists so that XmlInstructions can be used as associative array keys.
- const pure nothrow scope @safe string toString();
-
Returns a string representation of this XmlInstruction
- const pure nothrow @nogc @property scope @safe bool isEmptyXML();
-
Returns false always
- class ProcessingInstruction: std.xml.Item;
-
Class representing a Processing Instruction section
- pure @safe this(string content);
-
Construct a Processing Instruction section
- Parameters:
string content
the body of the instruction segment
- Throws:
- PIException if the segment body is illegal (contains "?>")
- Example
auto item = new ProcessingInstruction("php"); // constructs <?php?>
- const bool opEquals(scope const Object o);
-
Compares two processing instructions for equality
- Example
ProcessingInstruction item1,item2; if (item1 == item2) { }
- const scope int opCmp(scope const Object o);
-
Compares two processing instructions
You should rarely need to call this function. It exists so that ProcessingInstructions can be used as associative array keys.
- Example
ProcessingInstruction item1,item2; if (item1 < item2) { }
- const nothrow scope size_t toHash();
-
Returns the hash of a ProcessingInstruction
You should rarely need to call this function. It exists so that ProcessingInstructions can be used as associative array keys.
- const pure nothrow scope @safe string toString();
-
Returns a string representation of this ProcessingInstruction
- const pure nothrow @nogc @property scope @safe bool isEmptyXML();
-
Returns false always
- abstract class Item;
-
Abstract base class for XML items
- abstract const @safe bool opEquals(scope const Object o);
-
Compares with another Item of same type for equality
- abstract const @safe int opCmp(scope const Object o);
-
Compares with another Item of same type
- abstract const scope @safe size_t toHash();
-
Returns the hash of this item
- abstract const scope @safe string toString();
-
Returns a string representation of this item
- const scope @safe string[] pretty(uint indent);
-
Returns an indented string representation of this item
- Parameters:
uint indent
number of spaces by which to indent child elements
- abstract const pure nothrow @nogc @property scope @safe bool isEmptyXML();
-
Returns true if the item represents empty XML text
- class DocumentParser: std.xml.ElementParser;
-
Class for parsing an XML Document.
This is a subclass of ElementParser. Most of the useful functions are documented there.
- Standards:
- XML 1.0
- Bugs:
- Currently only supports UTF documents. If there is an encoding attribute in the prolog, it is ignored.
- this(string xmlText_);
-
Constructs a DocumentParser.
The input to this function MUST be valid XML. This is enforced by the function's in contract.
- Parameters:
string xmlText_
the entire XML document as text
- class ElementParser;
-
Class for parsing an XML element.
- Standards:
- XML 1.0 Note that you cannot construct instances of this class directly. You can construct a DocumentParser (which is a subclass of ElementParser), but otherwise, Instances of ElementParser will be created for you by the library, and passed your way via onStartTag handlers.
- const pure nothrow @nogc @property @safe const(Tag) tag();
-
The Tag at the start of the element being parsed. You can read this to determine the tag's name and attributes.
- ParserHandler[string] onStartTag;
-
Register a handler which will be called whenever a start tag is encountered which matches the specified name. You can also pass null as the name, in which case the handler will be called for any unmatched start tag.
- Example
// Call this function whenever a <podcast> start tag is encountered onStartTag["podcast"] = (ElementParser xml) { // Your code here // // This is a a closure, so code here may reference // variables which are outside of this scope }; // call myEpisodeStartHandler (defined elsewhere) whenever an <episode> // start tag is encountered onStartTag["episode"] = &myEpisodeStartHandler; // call delegate dg for all other start tags onStartTag[null] = dg;
This library will supply your function with a new instance of ElementHandler, which may be used to parse inside the element whose start tag was just found, or to identify the tag attributes of the element, etc. Note that your function will be called for both start tags and empty tags. That is, we make no distinction between <br></br> and <br/>. - ElementHandler[string] onEndTag;
-
Register a handler which will be called whenever an end tag is encountered which matches the specified name. You can also pass null as the name, in which case the handler will be called for any unmatched end tag.
- Example
// Call this function whenever a </podcast> end tag is encountered onEndTag["podcast"] = (in Element e) { // Your code here // // This is a a closure, so code here may reference // variables which are outside of this scope }; // call myEpisodeEndHandler (defined elsewhere) whenever an </episode> // end tag is encountered onEndTag["episode"] = &myEpisodeEndHandler; // call delegate dg for all other end tags onEndTag[null] = dg;
Note that your function will be called for both start tags and empty tags. That is, we make no distinction between <br></br> and <br/>. - pure nothrow @nogc @property @safe void onText(Handler handler);
-
Register a handler which will be called whenever text is encountered.
- Example
// Call this function whenever text is encountered onText = (string s) { // Your code here // The passed parameter s will have been decoded by the time you see // it, and so may contain any character. // // This is a a closure, so code here may reference // variables which are outside of this scope };
- pure nothrow @nogc @safe void onTextRaw(Handler handler);
-
Register an alternative handler which will be called whenever text is encountered. This differs from onText in that onText will decode the text, whereas onTextRaw will not. This allows you to make design choices, since onText will be more accurate, but slower, while onTextRaw will be faster, but less accurate. Of course, you can still call decode() within your handler, if you want, but you'd probably want to use onTextRaw only in circumstances where you know that decoding is unnecessary.
- Example
// Call this function whenever text is encountered onText = (string s) { // Your code here // The passed parameter s will NOT have been decoded. // // This is a a closure, so code here may reference // variables which are outside of this scope };
- pure nothrow @nogc @property @safe void onCData(Handler handler);
-
Register a handler which will be called whenever a character data segment is encountered.
- Example
// Call this function whenever a CData section is encountered onCData = (string s) { // Your code here // The passed parameter s does not include the opening <![CDATA[ // nor closing ]]> // // This is a a closure, so code here may reference // variables which are outside of this scope };
- pure nothrow @nogc @property @safe void onComment(Handler handler);
-
Register a handler which will be called whenever a comment is encountered.
- Example
// Call this function whenever a comment is encountered onComment = (string s) { // Your code here // The passed parameter s does not include the opening <!-- nor // closing --> // // This is a a closure, so code here may reference // variables which are outside of this scope };
- pure nothrow @nogc @property @safe void onPI(Handler handler);
-
Register a handler which will be called whenever a processing instruction is encountered.
- Example
// Call this function whenever a processing instruction is encountered onPI = (string s) { // Your code here // The passed parameter s does not include the opening <? nor // closing ?> // // This is a a closure, so code here may reference // variables which are outside of this scope };
- pure nothrow @nogc @property @safe void onXI(Handler handler);
-
Register a handler which will be called whenever an XML instruction is encountered.
- Example
// Call this function whenever an XML instruction is encountered // (Note: XML instructions may only occur preceding the root tag of a // document). onPI = (string s) { // Your code here // The passed parameter s does not include the opening <! nor // closing > // // This is a a closure, so code here may reference // variables which are outside of this scope };
- void parse();
-
Parse an XML element.
Parsing will continue until the end of the current element. Any items encountered for which a handler has been registered will invoke that handler.
- Throws:
- various kinds of XMLException
- const pure nothrow @nogc @safe string toString();
-
Returns that part of the element which has already been parsed
- pure @safe void check(string s);
-
Check an entire XML document for well-formedness
- Parameters:
string s
the document to be checked, passed as a string
- Throws:
- CheckException if the document is not well formed CheckException's toString() method will yield the complete hierarchy of parse failure (the XML equivalent of a stack trace), giving the line and column number of every failure at every level.
- class XMLException: object.Exception;
-
The base class for exceptions thrown by this module
- class CommentException: std.xml.XMLException;
-
Thrown during Comment constructor
- class CDataException: std.xml.XMLException;
-
Thrown during CData constructor
- class XIException: std.xml.XMLException;
-
Thrown during XMLInstruction constructor
- class PIException: std.xml.XMLException;
-
Thrown during ProcessingInstruction constructor
- class TextException: std.xml.XMLException;
-
Thrown during Text constructor
- class DecodeException: std.xml.XMLException;
-
Thrown during decode()
- class InvalidTypeException: std.xml.XMLException;
-
Thrown if comparing with wrong type
- class TagException: std.xml.XMLException;
-
Thrown when parsing for Tags
- class CheckException: std.xml.XMLException;
-
Thrown during check()
- CheckException err;
-
Parent in hierarchy
- string msg;
-
Name of production rule which failed to parse, or specific error message
- size_t line;
-
Line number at which parse failure occurred
- size_t column;
-
Column number at which parse failure occurred
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Licensed under the Boost License 1.0.
https://dlang.org/phobos/std_xml.html