XML versus the New Kids on the Block (PHPBNL11 2011-01-29)

XML VS.THE NEW KIDS ON THE BLOCK

David Zülke

David Zuelke

http://en.wikipedia.org/wiki/File:München_Panorama.JPG

Founder

Lead Developer

@dzuelke

TODAYS MENU• XML (and where it took a wrong turn)• HTML 5 (and why it makes me very, very angry)• JSON (and why its not always as useful as you may think)• YAML (and why it makes my eyes bleed)

but ﬁrst

Id like to hear from you, dear audience

what do you love, hate, adore or loathe with a passion?

XMLeXtensible Markup Language

"extensible" mostly refers to the Namespaces concept

VALIDATION• XML Schema (validates the grammar of a document)• RELAX NG (like XML Schema, just full of win) • Except its so awesome it sucks at reporting errors :(• Schematron (validates the semantics of a document)• DTD (RRRRRRRAAAAAAAAAAAAAAAAAGGGGEEEE)

OTHER GOODIES• XPath and XQuery for querying documents • XPath is an expression syntax, XQuery a full query language• XSLT to transform documents to XML, HTML, text, ... • Makes heavy use of XPath• XIncludes • Allow re-use of content within and across documents

READING AND WRITING• Push Parsing, uses events to notify app during parsing • Example: SAX• Pull Parsing, allows app to retrieve or skip elements • Example: PHPs ext/xmlreader• DOM, constructs an object representation of the tree • Example: DOM (duh)

but most importantly

Mixed Content!

<?xml version="1.0" encoding="utf-‐8"?><products xmlns="http://acme.com/shop/products"> <product id="123"> <name>Bacon</name> <price>5.99</price> </product></products>

<?xml version="1.0" encoding="utf-‐8"?><products xmlns="http://acme.com/shop/products"> <product id="123"> <name>Bacon</name> <price>5.99</price> OMNOMNOM Bacon </product></products>

and you can add elements without changing the structure

<?xml version="1.0" encoding="utf-‐8"?><products xmlns="http://acme.com/shop/products"> <product id="123"> <name>Bacon</name> <price>5.99</price> </product></products>

<?xml version="1.0" encoding="utf-‐8"?><products xmlns="http://acme.com/shop/products"> <product id="123"> <name xml:lang="en">Bacon</name> <name xml:lang="de">Speck</name> <price>5.99</price> </product></products>

<?xml version="1.0" encoding="utf-‐8"?><products xmlns="http://acme.com/shop/products"> <product id="123"> <name xml:lang="en">Bacon</name> <name xml:lang="de">Speck</name> <price>5.99</price> <link rel="category" href="..." /> </product></products>

XML: doing it right

<?xml version="1.0" encoding="utf-‐8" standalone="yes"?><search> <total_results>6</total_results> <items_per_page>2</items_per_page> <start_index>1</start_index> <link href="http://openapi.lovefilm.com/catalog/games?start_index=1&items_per_page=2&term=old" rel="self" title="self"/> <link href="http://openapi.lovefilm.com/catalog/games?start_index=3&items_per_page=2&term=old" rel="next" title="next"/> <link href="http://openapi.lovefilm.com/catalog/games?start_index=5&items_per_page=2&term=old" rel="last" title="last"/> <catalog_title> <can_rent>true</can_rent> <release_date>2003-‐09-‐12</release_date> <title full="Star Wars: Knights of the Old Republic" clean="Star Wars: Knights of the Old Republic"/> <id>http://openapi.lovefilm.com/catalog/title/59643</id> <adult>false</adult> <number_of_ratings>574</number_of_ratings> <rating>4</rating> <category scheme="http://openapi.lovefilm.com/categories/catalog" term="games"/> <category scheme="http://openapi.lovefilm.com/categories/format" term="Xbox"/> <category scheme="http://openapi.lovefilm.com/categories/genres" term="Adventure"/> <category scheme="http://openapi.lovefilm.com/categories/genres" term="Role-‐playing"/> <category scheme="http://openapi.lovefilm.com/categories/certificates/bbfc" term="TBC"/> <link href="http://openapi.lovefilm.com/catalog/title/59643/synopsis" rel="http://schemas.lovefilm.com/synopsis" title="synopsis"/> <link href="http://openapi.lovefilm.com/catalog/title/59643/reviews" rel="http://schemas.lovefilm.com/reviews" title="reviews"/> <link href="http://www.lovefilm.com/product/59643-‐Star-‐Wars-‐Knights-‐of-‐the-‐Old-‐Republic.html?cid=LFAPI" rel="alternate" title="web page"/> </catalog_title></search>

which brings me to...

HATEOAS AND HYPERMEDIA The Main Ingredient For Your REST API

XML: doing it wrong

<?xml version="1.0" encoding="UTF-‐8"?><!DOCTYPE plist PUBLIC "-‐//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-‐1.0.dtd"><plist version="1.0"><dict> <key>DefaultProfileChoices</key> <dict> <key>AC Power</key> <integer>2</integer> <key>Battery Power</key> <integer>1</integer> <key>UPS Power</key> <integer>1</integer> </dict> <key>SystemProfileDefaults</key> <array><!-‐-‐ Profile 0 -‐-‐> <dict><!-‐-‐ AC Power -‐ unused -‐-‐> <key>AC Power</key> <dict> <!-‐-‐ ... -‐-‐> </dict> </dict> </array></dict></plist>

but pleasedo not serialize objects to XML (Im looking at you, SOAP)

HTML 5Such a mess :(

HTML 5• Neither SGML nor XML • so browser vendors need to write new (inefﬁcient) parsers• Does not have a DTD anymore • how could it, given how its not SGML...• Completely idiotic stuff like data-* attributes • And theyre even proud of it...

<li class="user" data-‐name="John Resig" data-‐city="Boston" data-‐lang="js" data-‐food="Bacon"> John says: Hello, how are you?</li>

but thats already possible in XML!

<li class="user" xmlns:myapp="http://myapp.com/v1" myapp:name="John Resig" myapp:city="Boston" myapp:lang="js" myapp:food="Bacon"> John says: Hello, how are you?</li>

they dropped support for PUT & DELETE in forms

JSONJavaScript Object Notation

JSON KEY FEATURES• Quite efﬁcient, simple, universally supported in many languages• Very good for serializing objects• Built-in types, do not need explicit declaration• No schemas• No mixed content

win: store arbitrary keys and values

{ "_id" : "bc2a41170621c326ec68382f846d5764", "_rev" : "2612672603", "item" : "orange", "prices" : { "Fresh Mart" : 1.99, "Price Max" : 3.19, "Citrus Circus" : 1.09 }}

fail: use it as query language for your pile of crap database

{ foo: "bar" }{ x : 3, y : "foo" }{ $or : [ { a : 1 } , { b : 2 } ] }{ j : { $ne: 3 }, k : { $gt: 10 } }{ x : 3 }, { z : 1 }{ j : { $in : [2,4,6] } }{ "author.name" : "joe" }{ "addresses.city" : "London" }

YAMLYet Another Markup Language

YAMLYet Another Markup LanguageYAML Aint Markup Language

recursive acronyms are cool

YAML also was cool at some point

a simple markup language, perfect for conﬁguration ﬁles

autoload: # plugins plugins_lib: name: plugins lib path: %SF_PLUGINS_DIR%/*/lib recursive: true exclude: [] plugins_module_lib: name: plugins module lib path: %SF_PLUGINS_DIR%/*/modules/*/lib prefix: 2 recursive: true exclude: [] # project project: name: project path: %SF_LIB_DIR% recursive: true exclude: [model, symfony, deprecated]

but then...

foo: | -‐-‐-‐ foo: bar -‐-‐-‐ yo: bazbar: | fooness clipped: | This has one newline.same as "clipped" above: "This has one newline.n"stripped: |-‐ This has no newline.same as "stripped" above: "This has no newline."kept: |+ This has four newlines.same as "kept" above: "This has four newlines.nnnn"-‐ &showell Steve-‐ Clark -‐ Brian -‐ Oren -‐ *showell

YAML DRAWBACKS• Makes your eyes bleed• No schemas or other forms of validation• Forgeta newline somewhere and the parser might look at you, helpless, like a deer in headlights• No mixed content

CONCLUSION• XML for hypermedia, documents, your new REST API• JSON for serializing objects and storing them in e.g. CouchDB• YAML for your conﬁguration ﬁles

!e End

Questions?

THANK YOU! This was http://joind.in/2414 by @dzuelkeSend me questions or hire us:david.zuelke@bitextender.com

XML versus the New Kids on the Block (PHPBNL11 2011-01-29)

by David Zuelke

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