itextpdf html 样式,从使用 itext 创建的 PDF 中删除 HTML 和 CSS 样式

itextpdf html 样式,从使用 itext 创建的 PDF 中删除 HTML 和 CSS 样式

我们的应用程序类似，我们有一个富文本编辑器(TinyMCE)，我们的输出是通过 iText PDF 生成的 PDF。我们希望 HTML 尽可能干净，理想情况下只使用 iText 的 HTMLWorker 支持的 HTML 标签。 TinyMCE 可以做到这一点，但仍然存在最终用户可以提交 HTML 的情况，这实际上搞砸了，这可能会破坏 iText 生成 PDF 的能力。

我们使用 jSoup 和 jTidy CSSParser 的组合来过滤掉在 HTML“样式”属性中输入的不需要的 CSS 样式。输入 TinyMCE 的 HTML 使用此服务进行清理，该服务可以清除文字标记中的任何粘贴(如果用户没有使用 TinyMCE 中的“从 Word 粘贴”按钮)，并为我们提供了可以很好地转换为 iTextPDFs HTMLWorker 的 HTML。

我还在 iText 的 HTMLWorker 解析器(5.0.6)中发现表宽度问题，如果表格宽度在 style 属性中，HTMLWorker 忽略它并将表格宽度设置为 0，所以这是修复下面的一些逻辑。我们使用以下库：a

com.itextpdf:itextpdf:5.0.6 // used to generate PDFs

org.jsoup:jsoup:1.5.2 // used for cleaning HTML, primary cleaner

net.sf.jtidy:jtidy:r938 // used for cleaning HTML, secondary cleaner

net.sourceforge.cssparser:cssparser:0.9.5 // used to parse out unwanted HTML "style" attribute values

下面是我们为擦除 HTML 而构建的 Groovy 服务中的一些代码，只保留 iText 支持的标记和样式属性修复了表问题。代码中有一些特定于我们的应用程序的假设。这对我们来说非常有用。

import com.steadystate.css.parser.CSSOMParser

import org.htmlcleaner.CleanerProperties

import org.htmlcleaner.HtmlCleaner;

import org.htmlcleaner.PrettyHtmlSerializer

import org.htmlcleaner.SimpleHtmlSerializer

import org.htmlcleaner.TagNode

import org.jsoup.Jsoup

import des.Document

import org.jsoup.safety.Cleaner

import org.jsoup.safety.Whitelist

import org.jsoup.select.Elements

import org.w3c.css.sac.InputSource

import org.w3c.dom.css.CSSRule

import org.w3c.dom.css.CSSRuleList

import org.w3c.dom.css.CSSStyleDeclaration

import org.w3c.dom.css.CSSStyleSheet

import org.w3c.tidy.Tidy

class HtmlCleanerService {

static transactional = true

def cleanHTML(def html) {

// clean with JSoup which should filter out most unwanted things and

// ensure good html syntax

html = soupClean(html);

// run through JTidy to remove repeated nested tags, clean anything JSoup left out

html = tidyClean(html);

return html;

}

def tidyClean(def html) {

Tidy tidy = new Tidy()

tidy.setAsciiChars(true)

tidy.setDropEmptyParas(true)

tidy.setDropProprietaryAttributes(true)

tidy.setPrintBodyOnly(true)

tidy.setEncloseText(true)

tidy.setJoinStyles(true)

tidy.setLogicalEmphasis(true)

tidy.setQuoteMarks(true)

tidy.setHideComments(true)

tidy.setWraplen(120)

// (makeClean || dropFontTags) = replaces presentational markup by style rules

tidy.setMakeClean(true) // remove presentational clutter.

tidy.setDropFontTags(true)

// word2000 = drop style & class attributes and empty p, span elements

// draconian cleaning for Word2000

tidy.setWord2000(true)

tidy.setMakeBare(true) // remove Microsoft cruft.

tidy.setRepeatedAttributes(org.w3c.tidy.Configuration.KEEP_FIRST) // keep first or last duplicate attribute

// TODO ? tidy.setForceOutput(true)

def reader = new StringReader(html);

def writer = new StringWriter();

// hide output from stderr

tidy.setShowWarnings(false)

tidy.setErrout(new PrintWriter(new StringWriter()))

tidy.parse(reader, writer); // run tidy, providing an input and output stream

String()

}

def soupClean(def html) {

// clean the html

Document dirty = Jsoup.parseBodyFragment(html);

Cleaner cleaner = new Cleaner(createWhitelist());

Document clean = cleaner.clean(dirty);

// now hunt down all style attributes and ensure we only have those that render with iTextPDF

Elements styledNodes = clean.select("[style]"); // a with href

styledNodes.each { element ->

def style = element.attr("style");

def tag = element.tagName().toLowerCase()

def newstyle = ""

CSSOMParser parser = new CSSOMParser();

InputSource is = new InputSource(new StringReader(style))

CSSStyleDeclaration styledeclaration = parser.parseStyleDeclaration(is)

boolean hasProps = false

for (int i=0; i < Length(); i++) {

def propname = styledeclaration.item(i)

def propval = PropertyValue(propname)

propval = propval ? im() : ""

if (["padding-left", "text-decoration", "text-align", "font-weight", "font-style"].contains(propname)) {

newstyle = newstyle + propname + ": " + propval + ";"

hasProps = true

}

// standardize table widths, itextPDF won't render tables if there is only width in the

// style attribute. Here we ensure the width is in its own attribute, and change the value so

// it is in percentage and no larger than 100% to avoid end users from creating really goofy

// tables that they can't edit properly becuase they have made the width too large.

//

// width of the display area in the editor is about 740px, so let's ensure everything

// is relative to that

//

// TODO could get into trouble with nested tables and widths within as we assume

// one table (e.g. could have nested tables both with widths of 500)

if (tag.equals("table") && propname.equals("width")) {

if (dsWith("%")) {

// ensure it is <= 100%

propval = placeAll(~"[^0-9]", "")

propval = Math.min(100, Integer())

}

else {

// else we have measurement in px or assumed px, clean up and

// get integer value, then calculate a percentage

propval = placeAll(~"[^0-9]", "")

propval = Math.min(100, (int) (Integer() / 740)*100)

}

element.attr("width", propval + "%")

}

}

if (hasProps) {

element.attr("style", newstyle)

} else {