Refactoring of facebook image

src/main/java/com/softwaremill/java_fp_example/contest/dorzepowski/DefaultImageUrl.java

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+package com.softwaremill.java_fp_example.contest.dorzepowski;
+
+class DefaultImageUrl implements ImageUrl {
+
+	@Override
+	public String toString() {
+		return "https://softwaremill.com/images/logo-vertical.023d8496.png";
+	}
+}

src/main/java/com/softwaremill/java_fp_example/contest/dorzepowski/FacebookImage.java

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+package com.softwaremill.java_fp_example.contest.dorzepowski;
+
+import javaslang.control.Option;
+
+class FacebookImage implements Image {
+
+	private final static String FACEBOOK_IMAGE_TAG = "og:image";
+
+	private final ParsedPage parsedPage;
+
+	private FacebookImage(ParsedPage parsedPage) {
+		this.parsedPage = parsedPage;
+	}
+
+	static FacebookImage from(ParsedPage parsedPage) {
+		return new FacebookImage(parsedPage);
+	}
+
+	@Override
+	public ImageUrl url() {
+		return facebookImageUrl().getOrElse(DefaultImageUrl::new);
+	}
+
+	private Option<ImageUrl> facebookImageUrl() {
+		return imageUrlOf(contentFrom(firstImageElement()));
+	}
+
+	private Option<ImageUrl> imageUrlOf(Option<String> url) {
+		return url.map(FacebookImageUrl::new);
+	}
+
+	private Option<String> contentFrom(Option<ParsedElement> parsedElements) {
+		return parsedElements.map(ParsedElement::content);
+	}
+
+	private Option<ParsedElement> firstImageElement() {
+		return parsedPage.elementsByProperty(FACEBOOK_IMAGE_TAG).headOption();
+	}
+
+}

src/main/java/com/softwaremill/java_fp_example/contest/dorzepowski/FacebookImageUrl.java

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+package com.softwaremill.java_fp_example.contest.dorzepowski;
+
+class FacebookImageUrl implements ImageUrl {
+
+	private final String url;
+
+	FacebookImageUrl(String url) {
+		this.url = url;
+	}
+
+	@Override
+	public String toString() {
+		return url;
+	}
+}

src/main/java/com/softwaremill/java_fp_example/contest/dorzepowski/Image.java

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+package com.softwaremill.java_fp_example.contest.dorzepowski;
+
+public interface Image {
+
+	ImageUrl url();
+}

src/main/java/com/softwaremill/java_fp_example/contest/dorzepowski/ImageUrl.java

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+package com.softwaremill.java_fp_example.contest.dorzepowski;
+
+public interface ImageUrl {
+
+}

src/main/java/com/softwaremill/java_fp_example/contest/dorzepowski/LICENSE.txt

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+MIT License
+
+Copyright (c) 2017 dorzepowski
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

src/main/java/com/softwaremill/java_fp_example/contest/dorzepowski/Page.java

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+package com.softwaremill.java_fp_example.contest.dorzepowski;
+
+import java.net.URL;
+
+
+public class Page {
+
+	private final URL pageUrl;
+
+	public Page(URL pageUrl) {
+		this.pageUrl = pageUrl;
+	}
+
+	public Image facebookImage() {
+		return FacebookImage.from(new ParsedPage(pageUrl));
+	}
+
+}

src/main/java/com/softwaremill/java_fp_example/contest/dorzepowski/ParsedElement.java

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+package com.softwaremill.java_fp_example.contest.dorzepowski;
+
+import org.jsoup.nodes.Element;
+
+class ParsedElement {
+
+	private final Element element;
+
+	ParsedElement(Element element) {
+		this.element = element;
+	}
+
+	String content() {
+		return element.attr("content");
+	}
+}

src/main/java/com/softwaremill/java_fp_example/contest/dorzepowski/ParsedPage.java

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+package com.softwaremill.java_fp_example.contest.dorzepowski;
+
+import java.io.IOException;
+import java.net.URL;
+import java.util.function.Function;
+
+import javaslang.collection.Stream;
+import javaslang.control.Try;
+import lombok.extern.slf4j.Slf4j;
+import org.jsoup.Jsoup;
+import org.jsoup.nodes.Document;
+import org.jsoup.nodes.Element;
+import org.jsoup.select.Elements;
+
+@Slf4j
+class ParsedPage {
+
+	private final static int TEN_SECONDS = 10_000;
+
+	private final URL pageUrl;
+
+	ParsedPage(URL pageUrl) {
+		this.pageUrl = pageUrl;
+	}
+
+	Stream<ParsedElement> elementsByProperty(String property) {
+		return makeParsedElementsWhen(onPage(foundElementsWithProperty(property)));
+	}
+
+	private Stream<ParsedElement> makeParsedElementsWhen(Stream<Element> foundElements) {
+		return foundElements.map(ParsedElement::new);
+	}
+
+	private Stream<Element> onPage(Function<? super Document, ? extends Elements> toFoundElements) {
+		return parsePage().flatMap(toFoundElements);
+	}
+
+	private Function<? super Document, ? extends Elements> foundElementsWithProperty(String property) {
+		return document -> document.head().getElementsByAttributeValue("property", property);
+	}
+
+	private Stream<Document> parsePage() {
+		return Try.of(this::parse).onFailure(this::logParsingProblem).toStream();
+	}
+
+	private Document parse() throws IOException {
+		return Jsoup.parse(pageUrl, TEN_SECONDS);
+	}
+
+	private void logParsingProblem(Throwable e) {
+		log.error("Unable to extract og:image from url {}. Problem: {}", pageUrl, e.getMessage());
+	}
+}

src/test/groovy/com/softwaremill/java_fp_example/contest/dorzepowski/FindFacebookImageUrlOnPageSpec.groovy

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+package com.softwaremill.java_fp_example.contest.dorzepowski
+
+import spock.lang.Specification
+
+class FindFacebookImageUrlOnPageSpec extends Specification {
+
+	public static
+	final String DEFAULT_IMAGE = "https://softwaremill.com/images/logo-vertical.023d8496.png"
+
+
+	def "Find facebook image url for page that contain such url"() {
+		given:
+			def urlWithImage = new URL("https://softwaremill.com/the-wrong-abstraction-recap/")
+			def page = new Page(urlWithImage)
+		when:
+			def facebookImageUrl = page.facebookImage().url()
+		then:
+			'https://softwaremill.com/images/uploads/2017/02/street-shoe-chewing-gum.0526d557.jpg' == facebookImageUrl.toString()
+	}
+
+
+	def "Find default url when retrieving facebook image url from not existing page"() {
+		given:
+			def notExistingUrl = new URL("http://i-do-not-exist.pl")
+			def page = new Page(notExistingUrl)
+		when:
+			def facebookImageUrl = page.facebookImage().url()
+		then:
+			DEFAULT_IMAGE == facebookImageUrl.toString()
+	}
+
+	def "Find default url when retrieving facebook image url from page that doesn't contain facebook image"() {
+		given:
+			def urlWithoutImage = new URL("https://twitter.com/softwaremill")
+			def page = new Page(urlWithoutImage)
+		when:
+			def facebookImageUrl = page.facebookImage().url()
+		then:
+			DEFAULT_IMAGE == facebookImageUrl.toString()
+	}
+
+	def "Find default url when url is null"() {
+		given:
+			def page = new Page(null)
+		when:
+			def facebookImageUrl = page.facebookImage().url()
+		then:
+			DEFAULT_IMAGE == facebookImageUrl.toString()
+	}
+}