452 lines
11 KiB
Swift

//
// AtomParser.swift
// RSParser
//
// Created by Brent Simmons on 6/25/17.
// Copyright © 2017 Ranchero Software, LLC. All rights reserved.
//
import Foundation
import FoundationExtras
import SAX
import DateParser
final class AtomParser {
private var parserData: ParserData
private var feedURL: String {
parserData.url
}
private var data: Data {
parserData.data
}
private let feed: RSSFeed
private var articles = [RSSArticle]()
private var currentArticle: RSSArticle? {
articles.last
}
private var attributesStack = [StringDictionary]()
private var currentAttributes: StringDictionary? {
attributesStack.last
}
private var parsingXHTML = false
private var xhtmlString: String?
private var currentAuthor: RSSAuthor?
private var parsingAuthor = false
private var parsingArticle = false
private var parsingSource = false
private var endFeedFound = false
static func parsedFeed(with parserData: ParserData) -> RSSFeed {
let parser = AtomParser(parserData)
parser.parse()
return parser.feed
}
init(_ parserData: ParserData) {
self.parserData = parserData
self.feed = RSSFeed(urlString: parserData.url)
}
}
private extension AtomParser {
func parse() {
let saxParser = SAXParser(delegate: self, data: data)
saxParser.parse()
feed.articles = articles
}
private struct XMLName {
static let entry = "entry".utf8CString
static let content = "content".utf8CString
static let summary = "summary".utf8CString
static let link = "link".utf8CString
static let feed = "feed".utf8CString
static let source = "source".utf8CString
static let author = "author".utf8CString
static let name = "name".utf8CString
static let email = "email".utf8CString
static let uri = "uri".utf8CString
static let title = "title".utf8CString
static let id = "id".utf8CString
static let published = "published".utf8CString
static let updated = "updated".utf8CString
static let issued = "issued".utf8CString
static let modified = "modified".utf8CString
}
private struct XMLString {
static let rel = "rel"
static let alternate = "alternate"
static let related = "related"
static let enclosure = "enclosure"
static let href = "href"
static let title = "title"
static let type = "type"
static let length = "length"
static let xmlLang = "xml:lang"
}
func currentString(_ saxParser: SAXParser) -> String? {
saxParser.currentStringWithTrimmedWhitespace
}
func currentDate(_ saxParser: SAXParser) -> Date? {
guard let data = saxParser.currentCharacters else {
assertionFailure("Unexpected nil saxParser.currentCharacters in AtomParser.currentDate")
return nil
}
return DateParser.date(data: data)
}
func addFeedTitle(_ saxParser: SAXParser) {
guard feed.title == nil else {
return
}
if let title = currentString(saxParser), !title.isEmpty {
feed.title = title
}
}
func addFeedLink() {
guard feed.link == nil, let currentAttributes else {
return
}
if let related = currentAttributes[XMLString.rel], related == XMLString.alternate {
feed.link = currentAttributes[XMLString.href]
}
}
func addFeedLanguage() {
guard feed.language == nil, let currentAttributes else {
return
}
feed.language = currentAttributes[XMLString.xmlLang]
}
func addArticle() {
let article = RSSArticle(feedURL)
articles.append(article)
}
func addArticleElement(_ saxParser: SAXParser, _ localName: XMLPointer, _ prefix: XMLPointer?) {
guard prefix == nil else {
return
}
guard let currentArticle else {
assertionFailure("currentArticle must not be nil in AtomParser.addArticleElement")
return
}
if SAXEqualTags(localName, XMLName.id) {
currentArticle.guid = currentString(saxParser)
}
else if SAXEqualTags(localName, XMLName.title) {
currentArticle.title = currentString(saxParser)
}
else if SAXEqualTags(localName, XMLName.content) {
addContent(saxParser, currentArticle)
}
else if SAXEqualTags(localName, XMLName.summary) {
addSummary(saxParser, currentArticle)
}
else if SAXEqualTags(localName, XMLName.link) {
addLink(currentArticle)
}
else if SAXEqualTags(localName, XMLName.published) {
currentArticle.datePublished = currentDate(saxParser)
}
else if SAXEqualTags(localName, XMLName.updated) {
currentArticle.dateModified = currentDate(saxParser)
}
// Atom 0.3 dates
else if SAXEqualTags(localName, XMLName.issued) {
if currentArticle.datePublished == nil {
currentArticle.datePublished = currentDate(saxParser)
}
}
else if SAXEqualTags(localName, XMLName.modified) {
if currentArticle.dateModified == nil {
currentArticle.dateModified = currentDate(saxParser)
}
}
}
func addContent(_ saxParser: SAXParser, _ article: RSSArticle) {
article.body = currentString(saxParser)
}
func addSummary(_ saxParser: SAXParser, _ article: RSSArticle) {
guard article.body == nil else {
return
}
article.body = currentString(saxParser)
}
func addLink(_ article: RSSArticle) {
guard let attributes = currentAttributes else {
return
}
guard let urlString = attributes[XMLString.href], !urlString.isEmpty else {
return
}
var rel = attributes[XMLString.rel]
if rel?.isEmpty ?? true {
rel = XMLString.alternate
}
if rel == XMLString.related {
if article.link == nil {
article.link = urlString
}
}
else if rel == XMLString.alternate {
if article.permalink == nil {
article.permalink = urlString
}
}
else if rel == XMLString.enclosure {
if let enclosure = enclosure(urlString, attributes) {
article.addEnclosure(enclosure)
}
}
}
func enclosure(_ urlString: String, _ attributes: StringDictionary) -> RSSEnclosure? {
let enclosure = RSSEnclosure(url: urlString)
enclosure.title = attributes[XMLString.title]
enclosure.mimeType = attributes[XMLString.type]
if let lengthString = attributes[XMLString.length] {
enclosure.length = Int(lengthString)
}
return enclosure
}
func addXHTMLTag(_ localName: XMLPointer) {
guard var xhtmlString else {
assertionFailure("xhtmlString must not be nil when in addXHTMLTag.")
return
}
guard let name = String(xmlPointer: localName) else {
assertionFailure("Unexpected failure converting XMLPointer to String in addXHTMLTag.")
return
}
xhtmlString.append("<")
xhtmlString.append(name)
if let currentAttributes, currentAttributes.count > 0 {
for (key, value) in currentAttributes {
xhtmlString.append(" ")
xhtmlString.append(key)
xhtmlString.append("=\"")
let encodedValue = value.replacingOccurrences(of: "\"", with: "&quot;")
xhtmlString.append(encodedValue)
xhtmlString.append("\"")
}
}
xhtmlString.append(">")
}
}
extension AtomParser: SAXParserDelegate {
public func saxParser(_ saxParser: SAXParser, xmlStartElement localName: XMLPointer, prefix: XMLPointer?, uri: XMLPointer?, namespaceCount: Int, namespaces: UnsafePointer<XMLPointer?>?, attributeCount: Int, attributesDefaultedCount: Int, attributes: UnsafePointer<XMLPointer?>?) {
if endFeedFound {
return
}
let xmlAttributes = saxParser.attributesDictionary(attributes, attributeCount: attributeCount) ?? StringDictionary()
attributesStack.append(xmlAttributes)
if parsingXHTML {
addXHTMLTag(localName)
return
}
if SAXEqualTags(localName, XMLName.entry) {
parsingArticle = true
addArticle()
return
}
if SAXEqualTags(localName, XMLName.author) {
parsingAuthor = true
currentAuthor = RSSAuthor()
return
}
if SAXEqualTags(localName, XMLName.source) {
parsingSource = true
return
}
let isContentTag = SAXEqualTags(localName, XMLName.content)
let isSummaryTag = SAXEqualTags(localName, XMLName.summary)
if parsingArticle && (isContentTag || isSummaryTag) {
if isContentTag {
currentArticle?.language = xmlAttributes["xml:lang"]
}
let contentType = xmlAttributes["type"];
if contentType == "xhtml" {
parsingXHTML = true
xhtmlString = ""
return
}
}
if !parsingArticle && SAXEqualTags(localName, XMLName.link) {
addFeedLink()
return
}
if SAXEqualTags(localName, XMLName.feed) {
addFeedLanguage()
}
saxParser.beginStoringCharacters()
}
public func saxParser(_ saxParser: SAXParser, xmlEndElement localName: XMLPointer, prefix: XMLPointer?, uri: XMLPointer?) {
if SAXEqualTags(localName, XMLName.feed) {
endFeedFound = true
return
}
if endFeedFound {
return
}
if parsingXHTML {
let isContentTag = SAXEqualTags(localName, XMLName.content)
let isSummaryTag = SAXEqualTags(localName, XMLName.summary)
if parsingArticle && (isContentTag || isSummaryTag) {
if isContentTag {
currentArticle?.body = xhtmlString
}
else if isSummaryTag {
if (currentArticle?.body?.count ?? 0) < 1 {
currentArticle?.body = xhtmlString
}
}
}
if isContentTag || isSummaryTag {
parsingXHTML = false
}
if var xhtmlString {
if let localNameString = String(xmlPointer: localName) {
xhtmlString.append("</")
xhtmlString.append(localNameString)
xhtmlString.append(">")
}
} else {
assertionFailure("xhtmlString must not be nil when parsingXHTML in xmlEndElement.")
}
}
else if parsingAuthor {
if SAXEqualTags(localName, XMLName.author) {
parsingAuthor = false
if let currentAuthor, !currentAuthor.isEmpty() {
currentArticle?.addAuthor(currentAuthor)
}
currentAuthor = nil
}
else if SAXEqualTags(localName, XMLName.name) {
currentAuthor?.name = saxParser.currentStringWithTrimmedWhitespace
}
else if SAXEqualTags(localName, XMLName.email) {
currentAuthor?.emailAddress = saxParser.currentStringWithTrimmedWhitespace
}
else if SAXEqualTags(localName, XMLName.uri) {
currentAuthor?.url = saxParser.currentStringWithTrimmedWhitespace
}
}
else if SAXEqualTags(localName, XMLName.entry) {
parsingArticle = false
}
else if parsingArticle && !parsingSource {
addArticleElement(saxParser, localName, prefix)
}
else if SAXEqualTags(localName, XMLName.source) {
parsingSource = false
}
else if !parsingArticle && !parsingSource && SAXEqualTags(localName, XMLName.title) {
addFeedTitle(saxParser)
}
_ = attributesStack.popLast()
}
public func saxParser(_ saxParser: SAXParser, xmlCharactersFound: XMLPointer, count: Int) {
guard parsingXHTML else {
return
}
guard var s = String(xmlPointer: xmlCharactersFound, count: count) else {
return
}
// libxml decodes all entities; we need to re-encode certain characters
// (<, >, and &) when inside XHTML text content.
s = s.replacingOccurrences(of: "<", with: "&;lt;")
s = s.replacingOccurrences(of: ">", with: "&;gt;")
s = s.replacingOccurrences(of: "&", with: "&amp;")
xhtmlString = s
}
}