epubjs
Version:
Parse and Render Epubs
251 lines (217 loc) • 7.14 kB
JavaScript
import { defer } from "./utils/core";
import EpubCFI from "./epubcfi";
import Hook from "./utils/hook";
import { sprint } from "./utils/core";
import { replaceBase } from "./utils/replacements";
/**
* Represents a Section of the Book
* In most books this is equivelent to a Chapter
* @param {object} item The spine item representing the section
* @param {object} hooks hooks for serialize and content
*/
class Section {
constructor(item, hooks){
this.idref = item.idref;
this.linear = item.linear === "yes";
this.properties = item.properties;
this.index = item.index;
this.href = item.href;
this.url = item.url;
this.next = item.next;
this.prev = item.prev;
this.cfiBase = item.cfiBase;
if (hooks) {
this.hooks = hooks;
} else {
this.hooks = {};
this.hooks.serialize = new Hook(this);
this.hooks.content = new Hook(this);
}
this.document = undefined;
this.contents = undefined;
this.output = undefined;
}
/**
* Load the section from its url
* @param {method} _request a request method to use for loading
* @return {document} a promise with the xml document
*/
load(_request){
var request = _request || this.request || require("./utils/request");
var loading = new defer();
var loaded = loading.promise;
if(this.contents) {
loading.resolve(this.contents);
} else {
request(this.url)
.then(function(xml){
// var directory = new Url(this.url).directory;
this.document = xml;
this.contents = xml.documentElement;
return this.hooks.content.trigger(this.document, this);
}.bind(this))
.then(function(){
loading.resolve(this.contents);
}.bind(this))
.catch(function(error){
loading.reject(error);
});
}
return loaded;
}
/**
* Adds a base tag for resolving urls in the section
* @private
*/
base(){
return replaceBase(this.document, this);
}
/**
* Render the contents of a section
* @param {method} _request a request method to use for loading
* @return {string} output a serialized XML Document
*/
render(_request){
var rendering = new defer();
var rendered = rendering.promise;
this.output; // TODO: better way to return this from hooks?
this.load(_request).
then(function(contents){
var userAgent = (typeof navigator !== 'undefined' && navigator.userAgent) || '';
var isIE = userAgent.indexOf('Trident') >= 0;
var Serializer;
if (typeof XMLSerializer === "undefined" || isIE) {
Serializer = require("xmldom").XMLSerializer;
} else {
Serializer = XMLSerializer;
}
var serializer = new Serializer();
this.output = serializer.serializeToString(contents);
return this.output;
}.bind(this)).
then(function(){
return this.hooks.serialize.trigger(this.output, this);
}.bind(this)).
then(function(){
rendering.resolve(this.output);
}.bind(this))
.catch(function(error){
rendering.reject(error);
});
return rendered;
}
/**
* Find a string in a section
* @param {string} _query The query string to find
* @return {object[]} A list of matches, with form {cfi, excerpt}
*/
find(_query){
var section = this;
var matches = [];
var query = _query.toLowerCase();
var find = function(node){
var text = node.textContent.toLowerCase();
var range = section.document.createRange();
var cfi;
var pos;
var last = -1;
var excerpt;
var limit = 150;
while (pos != -1) {
// Search for the query
pos = text.indexOf(query, last + 1);
if (pos != -1) {
// We found it! Generate a CFI
range = section.document.createRange();
range.setStart(node, pos);
range.setEnd(node, pos + query.length);
cfi = section.cfiFromRange(range);
// Generate the excerpt
if (node.textContent.length < limit) {
excerpt = node.textContent;
}
else {
excerpt = node.textContent.substring(pos - limit/2, pos + limit/2);
excerpt = "..." + excerpt + "...";
}
// Add the CFI to the matches list
matches.push({
cfi: cfi,
excerpt: excerpt
});
}
last = pos;
}
};
sprint(section.document, function(node) {
find(node);
});
return matches;
};
/**
* Reconciles the current chapters layout properies with
* the global layout properities.
* @param {object} global The globa layout settings object, chapter properties string
* @return {object} layoutProperties Object with layout properties
*/
reconcileLayoutSettings(global){
//-- Get the global defaults
var settings = {
layout : global.layout,
spread : global.spread,
orientation : global.orientation
};
//-- Get the chapter's display type
this.properties.forEach(function(prop){
var rendition = prop.replace("rendition:", "");
var split = rendition.indexOf("-");
var property, value;
if(split != -1){
property = rendition.slice(0, split);
value = rendition.slice(split+1);
settings[property] = value;
}
});
return settings;
}
/**
* Get a CFI from a Range in the Section
* @param {range} _range
* @return {string} cfi an EpubCFI string
*/
cfiFromRange(_range) {
return new EpubCFI(_range, this.cfiBase).toString();
}
/**
* Get a CFI from an Element in the Section
* @param {element} el
* @return {string} cfi an EpubCFI string
*/
cfiFromElement(el) {
return new EpubCFI(el, this.cfiBase).toString();
}
/**
* Unload the section document
*/
unload() {
this.document = undefined;
this.contents = undefined;
this.output = undefined;
}
destroy() {
this.unload();
this.hooks.serialize.clear();
this.hooks.content.clear();
this.hooks = undefined;
this.idref = undefined;
this.linear = undefined;
this.properties = undefined;
this.index = undefined;
this.href = undefined;
this.url = undefined;
this.next = undefined;
this.prev = undefined;
this.cfiBase = undefined;
}
}
export default Section;