原文转载自道招网的[《# CKEditor系列（五）编辑器内容的设置和获取过程》](www.daozhao.com/10324.html)
我们看一下CKEditor4的编辑器内容的设置和获取过程，也就是setData和getData过程。
我们在调用editor.setData的时候，调用的就是core/editor.js里面的setData方法。
// src/core/editor.js
setData: function( data, options, internal ) {
var fireSnapshot = true,
// Backward compatibility.
callback = options,
eventData;
if ( options && typeof options == 'object' ) {
internal = options.internal;
callback = options.callback;
fireSnapshot = !options.noSnapshot;
}
if ( !internal && fireSnapshot )
this.fire( 'saveSnapshot' );
if ( callback || !internal ) {
this.once( 'dataReady', function( evt ) {
if ( !internal && fireSnapshot )
this.fire( 'saveSnapshot' );
if ( callback )
callback.call( evt.editor );
} );
}
// Fire "setData" so data manipulation may happen.
eventData = { dataValue: data };
!internal && this.fire( 'setData', eventData );
this._.data = eventData.dataValue;
!internal && this.fire( 'afterSetData', eventData );
},
我们可以看到里面的set过程实际是分三步
- 判断是否需要saveSnapshot
- 判断是否需要触发setData事件
- 判断是否需要触发afterSetData事件
setData之saveSnapshot
saveSnapshot主要是方便撤销操作的
// src/plugins/undo.plugin.js
// Save snapshots before doing custom changes.
editor.on( 'saveSnapshot', function( evt ) {
undoManager.save( evt.data && evt.data.contentOnly );
} );
setData之setData
我们接着看setData事件的处理
src/core/section.js
editor.on( 'setData', function() {
// Invalidate locked selection when unloading DOM.
// (https://dev.ckeditor.com/ticket/9521, https://dev.ckeditor.com/ticket/5217#comment:32 and https://dev.ckeditor.com/ticket/11500#comment:11)
editor.unlockSelection();
// Webkit's selection will mess up after the data loading.
if ( CKEDITOR.env.webkit )
clearSelection();
} );
我们可以看到，它做的工作主要是解锁选区，看来实际做工作的还不是setData啊，它算是一个setData的准备工作可能更合适些。
setData之afterSetData
// src/core/editable.js
this.attachListener( editor, 'afterSetData', function() {
this.setData( editor.getData( 1 ) );
}, this );
没错，这里又有个一个setData和getData。。。原来他们才是真正的setData和getData啊。
// src/core/editable.js
/**
* @see CKEDITOR.editor#setData
*/
setData: function( data, isSnapshot ) {
if ( !isSnapshot )
data = this.editor.dataProcessor.toHtml( data );
this.setHtml( data );
this.fixInitialSelection();
// Editable is ready after first setData.
if ( this.status == 'unloaded' )
this.status = 'ready';
this.editor.fire( 'dataReady' );
},
/**
* @see CKEDITOR.editor#getData
*/
getData: function( isSnapshot ) {
var data = this.getHtml();
if ( !isSnapshot )
data = this.editor.dataProcessor.toDataFormat( data );
return data;
},
setHtml和getHtml本质就是原生node的innerHTML，所以setData和getData的过程其实就是 this.editor.dataProcessor.toHtml和this.editor.dataProcessor.toDataFormat的过程，这个两个方法哪来的？它们都源自dataProcessor，它是在编辑器初始化的时候赋值的。
dataProcessor
// src/core/editor.js
// Various other core components that read editor configuration.
function initComponents( editor ) {
// Documented in dataprocessor.js.
editor.dataProcessor = new CKEDITOR.htmlDataProcessor( editor );
// Set activeFilter directly to avoid firing event.
editor.filter = editor.activeFilter = new CKEDITOR.filter( editor );
loadSkin( editor );
}
dataProcessor的两个具体方法如下
// src/core/dataProcessor.js
toHtml: function( data, options, fixForBody, dontFilter ) {
var editor = this.editor,
context, filter, enterMode, protectedWhitespaces;
// Typeof null == 'object', so check truthiness of options too.
if ( options && typeof options == 'object' ) {
context = options.context;
fixForBody = options.fixForBody;
dontFilter = options.dontFilter;
filter = options.filter;
enterMode = options.enterMode;
protectedWhitespaces = options.protectedWhitespaces;
}
// Backward compatibility. Since CKEDITOR 4.3.0 every option was a separate argument.
else {
context = options;
}
// Fall back to the editable as context if not specified.
if ( !context && context !== null )
context = editor.editable().getName();
return editor.fire( 'toHtml', {
dataValue: data,
context: context,
fixForBody: fixForBody,
dontFilter: dontFilter,
filter: filter || editor.filter,
enterMode: enterMode || editor.enterMode,
protectedWhitespaces: protectedWhitespaces
} ).dataValue;
},
toDataFormat: function( html, options ) {
var context, filter, enterMode;
// Do not shorten this to `options && options.xxx`, because
// falsy `options` will be passed instead of undefined.
if ( options ) {
context = options.context;
filter = options.filter;
enterMode = options.enterMode;
}
// Fall back to the editable as context if not specified.
if ( !context && context !== null )
context = this.editor.editable().getName();
return this.editor.fire( 'toDataFormat', {
dataValue: html,
filter: filter || this.editor.filter,
context: context,
enterMode: enterMode || this.editor.enterMode
} ).dataValue;
},
这两个方法的具体实现被化成对两个（toHtml和toDataFormat）事件的处理逻辑了。
dataProcessor之toHtml
这两个事件有哪些回调呢，先看toHtml。
// src/core/dataProcessor.js
editor.on( 'toHtml', function( evt ) {
var evtData = evt.data,
data = evtData.dataValue,
fixBodyTag;
// Before we start protecting markup, make sure there are no externally injected
// protection keywords.
data = removeReservedKeywords( data );
// The source data is already HTML, but we need to clean
// it up and apply the filter.
data = protectSource( data, editor );
// Protect content of textareas. (https://dev.ckeditor.com/ticket/9995)
// Do this before protecting attributes to avoid breaking:
// <textarea><img src="..." /></textarea>
data = protectElements( data, protectTextareaRegex );
// Before anything, we must protect the URL attributes as the
// browser may changing them when setting the innerHTML later in
// the code.
data = protectAttributes( data );
// Protect elements than can't be set inside a DIV. E.g. IE removes
// style tags from innerHTML. (https://dev.ckeditor.com/ticket/3710)
data = protectElements( data, protectElementsRegex );
// Certain elements has problem to go through DOM operation, protect
// them by prefixing 'cke' namespace. (https://dev.ckeditor.com/ticket/3591)
data = protectElementsNames( data );
// All none-IE browsers ignore self-closed custom elements,
// protecting them into open-close. (https://dev.ckeditor.com/ticket/3591)
data = protectSelfClosingElements( data );
// Compensate one leading line break after <pre> open as browsers
// eat it up. (https://dev.ckeditor.com/ticket/5789)
data = protectPreFormatted( data );
// There are attributes which may execute JavaScript code inside fixBin.
// Encode them greedily. They will be unprotected right after getting HTML from fixBin. (https://dev.ckeditor.com/ticket/10)
data = protectInsecureAttributes( data );
var fixBin = evtData.context || editor.editable().getName(),
isPre;
// Old IEs loose formats when load html into <pre>.
if ( CKEDITOR.env.ie && CKEDITOR.env.version < 9 && fixBin == 'pre' ) {
fixBin = 'div';
data = '<pre>' + data + '</pre>';
isPre = 1;
}
// Call the browser to help us fixing a possibly invalid HTML
// structure.
var el = editor.document.createElement( fixBin );
// Add fake character to workaround IE comments bug. (https://dev.ckeditor.com/ticket/3801)
el.setHtml( 'a' + data );
data = el.getHtml().substr( 1 );
// Restore shortly protected attribute names.
data = data.replace( new RegExp( 'data-cke-' + CKEDITOR.rnd + '-', 'ig' ), '' );
isPre && ( data = data.replace( /^<pre>|<\/pre>$/gi, '' ) );
// Unprotect "some" of the protected elements at this point.
data = unprotectElementNames( data );
data = unprotectElements( data );
// Restore the comments that have been protected, in this way they
// can be properly filtered.
data = unprotectRealComments( data );
if ( evtData.fixForBody === false ) {
fixBodyTag = false;
} else {
fixBodyTag = getFixBodyTag( evtData.enterMode, editor.config.autoParagraph );
}
// Now use our parser to make further fixes to the structure, as
// well as apply the filter.
data = CKEDITOR.htmlParser.fragment.fromHtml( data, evtData.context, fixBodyTag );
// The empty root element needs to be fixed by adding 'p' or 'div' into it.
// This avoids the need to create that element on the first focus (https://dev.ckeditor.com/ticket/12630).
if ( fixBodyTag ) {
fixEmptyRoot( data, fixBodyTag );
}
evtData.dataValue = data;
}, null, null, 5 );
// Filter incoming "data".
// Add element filter before htmlDataProcessor.dataFilter when purifying input data to correct html.
editor.on( 'toHtml', function( evt ) {
if ( evt.data.filter.applyTo( evt.data.dataValue, true, evt.data.dontFilter, evt.data.enterMode ) )
editor.fire( 'dataFiltered' );
}, null, null, 6 );
editor.on( 'toHtml', function( evt ) {
evt.data.dataValue.filterChildren( that.dataFilter, true );
}, null, null, 10 );
editor.on( 'toHtml', function( evt ) {
var evtData = evt.data,
data = evtData.dataValue,
writer = new CKEDITOR.htmlParser.basicWriter();
data.writeChildrenHtml( writer );
data = writer.getHtml( true );
// Protect the real comments again.
evtData.dataValue = protectRealComments( data );
}, null, null, 15 );
我们可以看到这些回调里面最多的几个单词就是protect和filter，它们主要也是做这些工作。
dataProcessor之toDataFormat
再看看toDataFormat的回调
// src/core/dataProcessor.js
editor.on( 'toDataFormat', function( evt ) {
var data = evt.data.dataValue;
// https://dev.ckeditor.com/ticket/10854 - we need to strip leading blockless <br> which FF adds
// automatically when editable contains only non-editable content.
// We do that for every browser (so it's a constant behavior) and
// not in BR mode, in which chance of valid leading blockless <br> is higher.
if ( evt.data.enterMode != CKEDITOR.ENTER_BR )
data = data.replace( /^<br *\/?>/i, '' );
evt.data.dataValue = CKEDITOR.htmlParser.fragment.fromHtml(
data, evt.data.context, getFixBodyTag( evt.data.enterMode, editor.config.autoParagraph ) );
}, null, null, 5 );
editor.on( 'toDataFormat', function( evt ) {
evt.data.dataValue.filterChildren( that.htmlFilter, true );
}, null, null, 10 );
// Transform outcoming "data".
// Add element filter after htmlDataProcessor.htmlFilter when preparing output data HTML.
editor.on( 'toDataFormat', function( evt ) {
evt.data.filter.applyTo( evt.data.dataValue, false, true );
}, null, null, 11 );
editor.on( 'toDataFormat', function( evt ) {
var data = evt.data.dataValue,
writer = that.writer;
writer.reset();
data.writeChildrenHtml( writer );
data = writer.getHtml( true );
// Restore those non-HTML protected source. (https://dev.ckeditor.com/ticket/4475,https://dev.ckeditor.com/ticket/4880)
data = unprotectRealComments( data );
data = unprotectSource( data, editor );
evt.data.dataValue = data;
}, null, null, 15 );
总结
编辑器内容的设置和获取表面上是简单只是调用一个方法就完成了，但是其实内部的流程还是很长的，大致分为：
- 消息告知
saveSnapshot - 准备工作
setData - 处理流程
dataProcessor - 发送事件
toHtml - 系统事件（优先级小于10）处理 protect和filter
- 系统事件（优先级大于10）处理，进行最后的兜底（插入或获取）逻辑
CKEDITOR.htmlParser.basicWriter
