I am curious to how browsers render xml in the presence of xsl? Is the html file generated an actual object? If so, is there a way to grab that html using Java Servlets, plain javascript, Nodejs or Expressjs?
Browsers have a built-in XSLT 1.0 processor which is invoked to transform the XML using the XSLT stylesheet. In some cases the built-in XSLT processor produces a DOM tree as output, in other cases it produces lexical HTML which is then parsed to construct a DOM.
If you want to perform the same operation on the server, there are plenty of XSLT processors available that you can invoke server-side. They come with an API that allows you to invoke the transformation, and in most cases they give you a range of options over how you want to capture the output, e.g. as an in-memory DOM (or DOM-like) tree, or as lexical XML or HTML.
Check what version of XSLT you want to use. The built-in processors in the browser only support XSLT 1.0, which is a rather ancient and restricted subset of the language; later versions (XSLT 2.0 and 3.0) have become much more powerful and user-friendly.
Related
I came across this service from stackoverflow
https://api.stackexchange.com/2.3/questions?fromdate=1519862400&todate=1522368000&order=desc&sort=activity&site=stackoverflow&tagged=python
I believe the source is from a database. How do I build an Xml to spit me out data in similar format?
I use the below logical lines
xmldoc.Load(xmlFileName);
Newtonsoft.Json.JsonConver.SerializeXmlNode(xmldoc);
Any recommendation of how to build the Xml which is a reverse process? My solutions are heavily dependant on Xml and flatFiles
According to https://api.stackexchange.com/docs the StackExchange API only supports JSON output, not XML. So you will have to convert the JSON to XML.
My own preference is to do this conversion "by hand" using XSLT 3.0 rather than using a standard library, because standard libraries often give you XML that's rather difficult to work with.
We have written XSLT's to transform XML files into HTML. We would like to have this HTML to be free from any vulnerabilities. There should not be any suspicious scripts running into it.
So, can we implement something in XSLT which will validate XML content and flag it as inappropriate to be written into HTML?
Yes, We do lot of sanitation of XML document.
XSLT is Open-source platform which is very advanced now. Here is the documentation, which helps you cleaning up and vulnerable less message object your XML document
For validation check and conditional based check you can use conditional operations in XSLT. We create templates in XSLT and make sure the XML object is very clean and vulnerable less.
Following is my requirement:
Application A is creating a JSON based on its Java Beans and sending to my Application.
I have to take this JSON and convert it into XML (XSD for this is completely different than my JSON structure) and send to Application B.
Solution 1) I am currently converting this json to xml using json.org library.Then using Apache-xalan and XSL stylesheet, I am converting this to xml format as required by App B.
Solution 2) Converting this json to Java Bean (JB1).Then converting this JB1 to another Java Bean (JB2) as per the xml structure required by Application B.Then convert JB2 to XML for app B.
Solution 3) Using Apache Xalan and Xerces to parse through the input json and make the XML in Java itself without using XSL.
Which is better approach (in simplicity of code, throughput )? As JSON becomes more complex, is it easy to use solution 1 ? Please suggest if there is better approach other than these 3 ?
XSLT 3.0 offers a built-in json-to-xml() function. Once you have the XML, you can easily transform it to your required format. It is implemented in Saxon 9.7 (PE or higher) and I believe in Exselt.
Solution 1: Yes. This is the conventional and best path for both simple and complex JSON and simple or complex targeted XML.
Solution 2: No. There's no reason to introduce Java Beans as an intermediate form, especially if you have no other need for Java Beans. This option unnecessarily introduces transformational and marshalling complexity.
Solution 3: No. Neither Xalan nor Xerces are designed to parse JSON; they are designed to parse XML.
There are sample programs that will map a JSON document into an equivalent XML document and back; I wrote one as a demo for Liberty's support of json-p (javax.json), using an XML vocabulary I called JinX (JSON in XML). That could be used as a pre/post processor wrapped around XSLT, if desired.
Better solutions are possible -- redefine XSLT to operate on JSON trees, for example -- but would take a bit more work.
JSON is, pure-and-simple, "a communications protocol." In other words, "it specifically exists(!) to allow 'arbitrary (JavaScript) data structures' to be conveyed between some-client and some-host," over "the HTTP(S) protocol."
Therefore: "it is not(!) XML," and therefore must never be considered to be "appropriate input to XSLT!"
"Thou shalt not mix Apples and Oranges!"
If you wish to apply "XSLT" technologies to a "JSON-derived" input (which is, by definition, "a data structure ...") then you must first, and "by whatever suitable means," convert that data structure into XML.
According to a post on Stackflow.com called “what’s is JSOn and why would I use it? “web services used XML as their primary data format for transmitting back data, but since JSON appeared, it is preferred method.” Why do must web services use JSON over XML, is because it’s a better method for interchanging?
XML was designed primarily for document formats, e.g. papers in scientific journals. It contains many features that aren't needed for simple data interchange, and these features can get in the way when you are processing XML because they can't be easily represented in Javascript. So the code for processing the XML ends up a lot more complicated than it could be. By contrasts, JSON has an exact match to the data structures Javascript can handle natively. Of course, that problem could in principle be solved by using a language with better XML support than JavaScript - XSLT, for example - but unfortunately XSLT in the browser has never had the same level of investment put into it.
Additionally, for reasons I have never understood, the browser security folks decided that reading JSON from alien web sites (i.e. from a different domain from your HTML page) is safe, but reading XML from alien sites isn't. So if you switch from XML to JSON, you get rid of a lot of cross-site-scripting hassle.
JSON is less verbose and it is sufficient for simple data transmission, i.e. if you do not need any transformations (XSLT).
I am trying to figure out how to parse HTML to XML, but I cannot figure it out. I want to use the MSXML2.ServerXMLHTTP object (in an .asp file).
<%
url = "http://www.website.com/file.asp"
set xmlhttp = CreateObject("MSXML2.ServerXMLHTTP")
xmlhttp.open "POST", url, false
xmlhttp.send
Response.write xmlhttp.responseText
set xmlhttp = nothing
%>
This gives me the text, but I really don't know where to go from here.
I think problem is in HEAD of HTML file.
From MSDN: resonse should return XML ("text/xml"), but your http://www.website.com/file.asp returns HTML content, with ("text/html") mime type.
Native XML Extensions
I prefer using one of the native XML extensions since they come bundled with PHP, are usually faster than all the 3rd party libs and give me all the control I need over the markup.
DOM
The DOM extension allows you to operate on XML documents through the DOM API with PHP 5. It is an implementation of the W3C's Document Object Model Core Level 3, a platform- and language-neutral interface that allows programs and scripts to dynamically access and update the content, structure and style of documents.
DOM is capable of parsing and modifying real world (broken) HTML and it can do XPath queries. It is based on libxml.
It takes some time to get productive with DOM, but that time is well worth it IMO. Since DOM is a language-agnostic interface, you'll find implementations in many languages, so if you need to change your programming language, chances are you will already know how to use that language's DOM API then.
A basic usage example can be found in grabbing the href attribute of an A element and a general conceptual overview can be found at DOMDocument in PHP.
How to use the DOM extension has been covered extensively on StackOverflow, so if you choose to use it, you can be sure most of the issues you run into can be solved by searching/browsing StackOverflow.
XMLReader
The XMLReader extension is an XML pull parser. The reader acts as a cursor going forward on the document stream and stopping at each node on the way.
XMLReader, like DOM, is based on libxml. I am not aware of how to trigger the HTML Parser Module, so chances are using XMLReader for parsing broken HTML might be less robust than using DOM where you can explicitly tell it to use libxml's HTML parser module.
A basic usage example can be found at getting all values from h1 tags using PHP.
XML Parser
This extension lets you create XML parsers and then define handlers for different XML events. Each XML parser also has a few parameters you can adjust.
The XML Parser library is also based on libxml, and implements a SAX style XML push parser. It may be a better choice for memory management than DOM or SimpleXML, but will be more difficult to work with than the pull parser implemented by XMLReader.
SimpleXml
The SimpleXML extension provides a very simple and easily usable toolset to convert XML to an object that can be processed with normal property selectors and array iterators.
SimpleXML is an option when you know the HTML is valid XHTML. If you need to parse broken HTML, don't even consider SimpleXml because it will choke.
A basic usage example can be found at A simple program to CRUD node and node values of xml file and there is lots of additional examples in the PHP manual.
3rd Party Libraries (libxml based)
If you prefer to use a 3rd-party lib, I'd suggest using a lib that actually uses DOM/libxml underneath instead of string parsing.
FluentDom - Repo
FluentDOM provides a jQuery-like fluent XML interface for the DOMDocument in PHP. Selectors are written in XPath or CSS (using a CSS to XPath converter). Current versions extend the DOM implementing standard interfaces and add features from the DOM Living Standard. FluentDOM can load formats like JSON, CSV, JsonML, RabbitFish and others. Can be installed via Composer.
HtmlPageDom
Wa72\HtmlPageDom` is a PHP library for easy manipulation of HTML documents using It requires DomCrawler from Symfony2 components for traversing the DOM tree and extends it by adding methods for manipulating the DOM tree of HTML documents.
phpQuery (not updated for years)
phpQuery is a server-side, chainable, CSS3 selector driven Document Object Model (DOM) API based on jQuery JavaScript Library written in PHP5 and provides additional Command Line Interface (CLI).
Also see: https://github.com/electrolinux/phpquery
Zend_Dom
Zend_Dom provides tools for working with DOM documents and structures. Currently, we offer Zend_Dom_Query, which provides a unified interface for querying DOM documents utilizing both XPath and CSS selectors.
QueryPath
QueryPath is a PHP library for manipulating XML and HTML. It is designed to work not only with local files, but also with web services and database resources. It implements much of the jQuery interface (including CSS-style selectors), but it is heavily tuned for server-side use. Can be installed via Composer.
fDOMDocument
fDOMDocument extends the standard DOM to use exceptions at all occasions of errors instead of PHP warnings or notices. They also add various custom methods and shortcuts for convenience and to simplify the usage of DOM.
sabre/xml
sabre/xml is a library that wraps and extends the XMLReader and XMLWriter classes to create a simple "XML to object/array" mapping system and design pattern. Writing and reading XML is single-pass and can therefore be fast and require low memory on large XML files.
FluidXML
FluidXML is a PHP library for manipulating XML with a concise and fluent API. It leverages XPath and the fluent programming pattern to be fun and effective.
3rd-Party (not libxml-based)
The benefit of building upon DOM/libxml is that you get good performance out of the box because you are based on a native extension. However, not all 3rd-party libs go down this route. Some of them listed below.
PHP Simple HTML DOM Parser
An HTML DOM parser written in PHP5+ lets you manipulate HTML in a very easy way!
Require PHP 5+.
Supports invalid HTML.
Find tags on an HTML page with selectors just like jQuery.
Extract contents from HTML in a single line.
I generally do not recommend this parser. The codebase is horrible and the parser itself is rather slow and memory hungry. Not all jQuery Selectors (such as child selectors) are possible. Any of the libxml based libraries should outperform this easily.
PHP Html Parser
PHPHtmlParser is a simple, flexible, HTML parser which allows you to select tags using any CSS selector, like jQuery. The goal is to assist in the development of tools which require a quick, easy way to scrape HTML, whether it's valid or not! This project was original supported by sunra/php-simple-html-dom-parser but the support seems to have stopped so this project is my adaptation of his previous work.
Again, I would not recommend this parser. It is rather slow with high CPU usage. There is also no function to clear memory of created DOM objects. These problems scale particularly with nested loops. The documentation itself is inaccurate and misspelled, with no responses to fixes since 14 Apr 16.
Ganon
A universal tokenizer and HTML/XML/RSS DOM parser
Ability to manipulate elements and their attributes
Supports invalid HTML and UTF8
Can perform advanced CSS3-like queries on elements (like jQuery -- namespaces supported)
A HTML beautifier (like HTML Tidy)
Minify CSS and Javascript
Sort attributes, change character case, correct indentation, etc.
Extensible
Parsing documents using callbacks based on current character/token
Operations separated in smaller functions for easy overriding
Fast and easy
Never used it. Can't tell if it's any good.
HTML 5
You can use the above for parsing HTML5, but there can be quirks due to the markup HTML5 allows. So for HTML5 you want to consider using a dedicated parser, like:
html5lib
A Python and PHP implementations of a HTML parser based on the WHATWG HTML5 specification for maximum compatibility with major desktop web browsers.
We might see more dedicated parsers once HTML5 is finalized. There is also a blogpost by the W3's titled How-To for html 5 parsing that is worth checking out.
WebServices
If you don't feel like programming PHP, you can also use Web services. In general, I found very little utility for these, but that's just me and my use cases.
ScraperWiki
ScraperWiki's external interface allows you to extract data in the form you want for use on the web or in your own applications. You can also extract information about the state of any scraper.
Regular Expressions
Last and least recommended, you can extract data from HTML with regular expressions. In general using Regular Expressions on HTML is discouraged.
Most of the snippets you will find on the web to match markup are brittle. In most cases they are only working for a very particular piece of HTML. Tiny markup changes, like adding whitespace somewhere, or adding, or changing attributes in a tag, can make the RegEx fails when it's not properly written. You should know what you are doing before using RegEx on HTML.
HTML parsers already know the syntactical rules of HTML. Regular expressions have to be taught for each new RegEx you write. RegEx are fine in some cases, but it really depends on your use-case.
You can write more reliable parsers, but writing a complete and reliable custom parser with regular expressions is a waste of time when the aforementioned libraries already exist and do a much better job on this.
Also see Parsing Html The Cthulhu Way
Books
If you want to spend some money, have a look at
PHP Architect's Guide to Webscraping with PHP
I am not affiliated with PHP Architect or the authors.