JavaScript Snippet Injection

instrumentation/servlet/servlet-3.0/javaagent-unit-tests/build.gradle.kts

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+plugins {
+ id("otel.java-conventions")
+}
+
+dependencies {
+ testImplementation("javax.servlet:javax.servlet-api:3.0.1")
+ testImplementation(project(":instrumentation:servlet:servlet-3.0:javaagent"))
+}

instrumentation/servlet/servlet-3.0/javaagent-unit-tests/src/test/java/io/opentelemetry/javaagent/instrumentation/servlet/v3_0/snippet/SnippetPrintWriterTest.java

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+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.javaagent.instrumentation.servlet.v3_0.snippet;
+
+import static io.opentelemetry.javaagent.instrumentation.servlet.v3_0.snippet.TestUtil.readFileAsString;
+import static org.assertj.core.api.AssertionsForClassTypes.assertThat;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.io.StringWriter;
+import java.nio.charset.Charset;
+import javax.servlet.http.HttpServletResponse;
+import javax.servlet.http.HttpServletResponseWrapper;
+import org.junit.jupiter.api.Test;
+
+class SnippetPrintWriterTest {
+
+ @Test
+ void testInjectToTextHtml() throws IOException {
+ String snippet = "\n <script type=\"text/javascript\"> Test </script>";
+ String html = readFileAsString("beforeSnippetInjection.html");
+
+ InMemoryHttpServletResponse response = createInMemoryHttpServletResponse("text/html");
+ SnippetInjectingResponseWrapper responseWrapper =
+ new SnippetInjectingResponseWrapper(response, snippet);
+
+ responseWrapper.getWriter().write(html);
+ responseWrapper.getWriter().flush();
+
+ String expectedHtml = readFileAsString("afterSnippetInjection.html");
+ assertThat(response.getStringContent()).isEqualTo(expectedHtml);
+ }
+
+ @Test
+ void testInjectToChineseTextHtml() throws IOException {
+ String snippet = "\n <script type=\"text/javascript\"> Test </script>";
+ String html = readFileAsString("beforeSnippetInjectionChinese.html");
+
+ InMemoryHttpServletResponse response = createInMemoryHttpServletResponse("text/html");
+ SnippetInjectingResponseWrapper responseWrapper =
+ new SnippetInjectingResponseWrapper(response, snippet);
+
+ responseWrapper.getWriter().write(html);
+ responseWrapper.getWriter().flush();
+
+ String expectedHtml = readFileAsString("afterSnippetInjectionChinese.html");
+ assertThat(response.getStringContent()).isEqualTo(expectedHtml);
+ }
+
+ @Test
+ void shouldNotInjectToTextHtml() throws IOException {
+ String snippet = "\n <script type=\"text/javascript\"> Test </script>";
+ String html = readFileAsString("beforeSnippetInjection.html");
+
+ InMemoryHttpServletResponse response = createInMemoryHttpServletResponse("not/text");
+
+ SnippetInjectingResponseWrapper responseWrapper =
+ new SnippetInjectingResponseWrapper(response, snippet);
+
+ responseWrapper.getWriter().write(html);
+ responseWrapper.getWriter().flush();
+
+ assertThat(response.getStringContent()).isEqualTo(html);
+ }
+
+ @Test
+ void testWriteInt() throws IOException {
+ String snippet = "\n <script type=\"text/javascript\"> Test </script>";
+ String html = readFileAsString("beforeSnippetInjection.html");
+
+ InMemoryHttpServletResponse response = createInMemoryHttpServletResponse("text/html");
+ SnippetInjectingResponseWrapper responseWrapper =
+ new SnippetInjectingResponseWrapper(response, snippet);
+
+ byte[] originalBytes = html.getBytes(Charset.defaultCharset());
+ for (byte originalByte : originalBytes) {
+ responseWrapper.getWriter().write(originalByte);
+ }
+ responseWrapper.getWriter().flush();
+
+ String expectedHtml = readFileAsString("afterSnippetInjection.html");
+ assertThat(response.getStringContent()).isEqualTo(expectedHtml);
+ }
+
+ @Test
+ void testWriteCharArray() throws IOException {
+ String snippet = "\n <script type=\"text/javascript\"> Test </script>";
+ String html = readFileAsString("beforeSnippetInjectionChinese.html");
+
+ InMemoryHttpServletResponse response = createInMemoryHttpServletResponse("text/html");
+ SnippetInjectingResponseWrapper responseWrapper =
+ new SnippetInjectingResponseWrapper(response, snippet);
+
+ char[] originalChars = html.toCharArray();
+ responseWrapper.getWriter().write(originalChars, 0, originalChars.length);
+ responseWrapper.getWriter().flush();
+
+ String expectedHtml = readFileAsString("afterSnippetInjectionChinese.html");
+ assertThat(response.getStringContent()).isEqualTo(expectedHtml);
+ }
+
+ @Test
+ void testWriteWithOffset() throws IOException {
+ String snippet = "\n <script type=\"text/javascript\"> Test </script>";
+ String html = readFileAsString("beforeSnippetInjectionChinese.html");
+ String extraBuffer = "this buffer should not be print out";
+ html = extraBuffer + html;
+
+ InMemoryHttpServletResponse response = createInMemoryHttpServletResponse("text/html");
+ SnippetInjectingResponseWrapper responseWrapper =
+ new SnippetInjectingResponseWrapper(response, snippet);
+
+ responseWrapper
+ .getWriter()
+ .write(html, extraBuffer.length(), html.length() - extraBuffer.length());
+ responseWrapper.getWriter().flush();
+
+ String expectedHtml = readFileAsString("afterSnippetInjectionChinese.html");
+ assertThat(response.getStringContent()).isEqualTo(expectedHtml);
+ }
+
+ private static InMemoryHttpServletResponse createInMemoryHttpServletResponse(String contentType) {
+ HttpServletResponse response = mock(HttpServletResponse.class);
+ when(response.getContentType()).thenReturn(contentType);
+ when(response.getStatus()).thenReturn(200);
+ when(response.containsHeader("content-type")).thenReturn(true);
+ return new InMemoryHttpServletResponse(response);
+ }
+
+ private static class InMemoryHttpServletResponse extends HttpServletResponseWrapper {
+
+ private PrintWriter printWriter;
+ private StringWriter stringWriter;
+
+ InMemoryHttpServletResponse(HttpServletResponse delegate) {
+ super(delegate);
+ }
+
+ @Override
+ public PrintWriter getWriter() {
+ if (printWriter == null) {
+ stringWriter = new StringWriter();
+ printWriter = new PrintWriter(stringWriter);
+ }
+ return printWriter;
+ }
+
+ String getStringContent() {
+ printWriter.flush();
+ return stringWriter.toString();
+ }
+ }
+}

instrumentation/servlet/servlet-3.0/javaagent-unit-tests/src/test/java/io/opentelemetry/javaagent/instrumentation/servlet/v3_0/snippet/SnippetServletOutputStreamTest.java

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+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.javaagent.instrumentation.servlet.v3_0.snippet;
+
+import static io.opentelemetry.javaagent.instrumentation.servlet.v3_0.snippet.TestUtil.readFileAsBytes;
+import static java.nio.charset.StandardCharsets.UTF_8;
+import static org.assertj.core.api.AssertionsForClassTypes.assertThat;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.nio.charset.Charset;
+import javax.servlet.ServletOutputStream;
+import javax.servlet.http.HttpServletResponse;
+import org.junit.jupiter.api.Test;
+
+class SnippetServletOutputStreamTest {
+
+ @Test
+ void testInjectionForStringContainHeadTag() throws IOException {
+ String snippet = "\n <script type=\"text/javascript\"> Test </script>";
+ byte[] html = readFileAsBytes("beforeSnippetInjection.html");
+
+ InjectionState obj = createInjectionStateForTesting(snippet, UTF_8);
+ InMemoryServletOutputStream out = new InMemoryServletOutputStream();
+
+ OutputStreamSnippetInjectionHelper helper = new OutputStreamSnippetInjectionHelper(snippet);
+ boolean injected = helper.handleWrite(obj, out, html, 0, html.length);
+ assertThat(obj.getHeadTagBytesSeen()).isEqualTo(-1);
+ assertThat(injected).isEqualTo(true);
+
+ byte[] expectedHtml = readFileAsBytes("afterSnippetInjection.html");
+ assertThat(out.getBytes()).isEqualTo(expectedHtml);
+ }
+
+ @Test
+ void testInjectionForChinese() throws IOException {
+ String snippet = "\n <script type=\"text/javascript\"> Test </script>";
+ byte[] html = readFileAsBytes("beforeSnippetInjectionChinese.html");
+
+ InjectionState obj = createInjectionStateForTesting(snippet, UTF_8);
+ InMemoryServletOutputStream out = new InMemoryServletOutputStream();
+
+ OutputStreamSnippetInjectionHelper helper = new OutputStreamSnippetInjectionHelper(snippet);
+ boolean injected = helper.handleWrite(obj, out, html, 0, html.length);
+
+ byte[] expectedHtml = readFileAsBytes("afterSnippetInjectionChinese.html");
+ assertThat(injected).isTrue();
+ assertThat(obj.getHeadTagBytesSeen()).isEqualTo(-1);
+ assertThat(out.getBytes()).isEqualTo(expectedHtml);
+ }
+
+ @Test
+ void testInjectionForStringWithoutHeadTag() throws IOException {
+ String snippet = "\n <script type=\"text/javascript\"> Test </script>";
+ byte[] html = readFileAsBytes("htmlWithoutHeadTag.html");
+
+ InjectionState obj = createInjectionStateForTesting(snippet, UTF_8);
+ InMemoryServletOutputStream out = new InMemoryServletOutputStream();
+
+ OutputStreamSnippetInjectionHelper helper = new OutputStreamSnippetInjectionHelper(snippet);
+ boolean injected = helper.handleWrite(obj, out, html, 0, html.length);
+
+ assertThat(injected).isFalse();
+ assertThat(obj.getHeadTagBytesSeen()).isEqualTo(0);
+ assertThat(out.getBytes()).isEmpty();
+ }
+
+ @Test
+ void testHeadTagSplitAcrossTwoWrites() throws IOException {
+ String snippet = "\n <script type=\"text/javascript\"> Test </script>";
+ String htmlFirstPart = "<!DOCTYPE html>\n<html lang=\"en\">\n<he";
+ byte[] htmlFirstPartBytes = htmlFirstPart.getBytes(UTF_8);
+
+ InjectionState obj = createInjectionStateForTesting(snippet, UTF_8);
+ InMemoryServletOutputStream out = new InMemoryServletOutputStream();
+
+ OutputStreamSnippetInjectionHelper helper = new OutputStreamSnippetInjectionHelper(snippet);
+ boolean injected =
+ helper.handleWrite(obj, out, htmlFirstPartBytes, 0, htmlFirstPartBytes.length);
+
+ assertThat(injected).isFalse();
+ assertThat(obj.getHeadTagBytesSeen()).isEqualTo(3);
+ assertThat(out.getBytes()).isEmpty();
+
+ String htmlSecondPart =
+ "ad>\n"
+ + " <meta charset=\"UTF-8\">\n"
+ + " <title>Title</title>\n"
+ + "</head>\n"
+ + "<body>\n"
+ + "\n"
+ + "</body>\n"
+ + "</html>";
+ byte[] htmlSecondPartBytes = htmlSecondPart.getBytes(UTF_8);
+ injected = helper.handleWrite(obj, out, htmlSecondPartBytes, 0, htmlSecondPartBytes.length);
+
+ assertThat(injected).isTrue();
+ assertThat(obj.getHeadTagBytesSeen()).isEqualTo(-1);
+
+ String expectedSecondPart =
+ "ad>\n"
+ + " <script type=\"text/javascript\"> Test </script>\n"
+ + " <meta charset=\"UTF-8\">\n"
+ + " <title>Title</title>\n"
+ + "</head>\n"
+ + "<body>\n"
+ + "\n"
+ + "</body>\n"
+ + "</html>";
+ assertThat(out.getBytes()).isEqualTo(expectedSecondPart.getBytes(UTF_8));
+ }
+
+ private static InjectionState createInjectionStateForTesting(String snippet, Charset charset) {
+ HttpServletResponse response = mock(HttpServletResponse.class);
+ when(response.isCommitted()).thenReturn(false);
+ when(response.getCharacterEncoding()).thenReturn(charset.name());
+
+ return new InjectionState(new SnippetInjectingResponseWrapper(response, snippet));
+ }
+
+ private static class InMemoryServletOutputStream extends ServletOutputStream {
+
+ private final ByteArrayOutputStream baos = new ByteArrayOutputStream();
+
+ @Override
+ public void write(int b) {
+ baos.write(b);
+ }
+
+ public byte[] getBytes() {
+ return baos.toByteArray();
+ }
+ }
+}

instrumentation/servlet/servlet-3.0/javaagent-unit-tests/src/test/java/io/opentelemetry/javaagent/instrumentation/servlet/v3_0/snippet/TestUtil.java

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+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.javaagent.instrumentation.servlet.v3_0.snippet;
+
+import static java.nio.charset.StandardCharsets.UTF_8;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+
+public class TestUtil {
+
+ protected static byte[] readFileAsBytes(String resourceName) throws IOException {
+ InputStream in =
+ SnippetPrintWriterTest.class.getClassLoader().getResourceAsStream(resourceName);
+ ByteArrayOutputStream result = new ByteArrayOutputStream();
+ byte[] buffer = new byte[1024];
+ int length;
+ while ((length = in.read(buffer)) != -1) {
+ result.write(buffer, 0, length);
+ }
+ return result.toByteArray();
+ }
+
+ protected static String readFileAsString(String resourceName) throws IOException {
+ return new String(readFileAsBytes(resourceName), UTF_8);
+ }
+
+ private TestUtil() {}
+}

instrumentation/servlet/servlet-3.0/javaagent-unit-tests/src/test/resources/afterSnippetInjection.html

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+<!DOCTYPE html>
+<html lang="en">
+<head>
+ <script type="text/javascript"> Test </script>
+ <meta charset="UTF-8">
+ <title>Title</title>
+</head>
+<body>
+
+</body>
+</html>

instrumentation/servlet/servlet-3.0/javaagent-unit-tests/src/test/resources/afterSnippetInjectionChinese.html

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+<!DOCTYPE html>
+<html lang="en">
+<head>
+ <script type="text/javascript"> Test </script>
+ <meta charset="UTF-8">
+ <title>Title</title>
+</head>
+<body>
+<p>欢迎光临</p>
+</body>
+</html>

instrumentation/servlet/servlet-3.0/javaagent-unit-tests/src/test/resources/beforeSnippetInjection.html

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+<!DOCTYPE html>
+<html lang="en">
+<head>
+ <meta charset="UTF-8">
+ <title>Title</title>
+</head>
+<body>
+
+</body>
+</html>

instrumentation/servlet/servlet-3.0/javaagent-unit-tests/src/test/resources/beforeSnippetInjectionChinese.html

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+<!DOCTYPE html>
+<html lang="en">
+<head>
+ <meta charset="UTF-8">
+ <title>Title</title>
+</head>
+<body>
+<p>欢迎光临</p>
+</body>
+</html>