Package io.karatelabs.output

Class HtmlReportWriter

java.lang.Object
io.karatelabs.output.HtmlReportWriter
public final class HtmlReportWriter extends Object
Generates HTML reports with inlined JSON data and Alpine.js client-side rendering.

This implementation uses a single-file HTML architecture where:

  • JSON data is inlined in a <script type="application/json"> tag
  • Alpine.js renders the content client-side
  • No server-side template rendering is required

Output structure: 

 target/karate-reports/
 ├── index.html                (redirects to karate-summary.html)
 ├── karate-summary.html       (summary page with tag filtering)
 ├── karate-timeline.html      (parallel-execution Gantt)
 ├── feature-html/
 │   └── {feature.path}.html   (per-feature reports, dot-based naming)
 ├── karate-json/karate-events.jsonl  (streamed during execution, opt-in)
 └── res/
     ├── bootstrap.min.css
     ├── alpine.min.js
     └── karate-report.css

  • Method Details

    • resetEmbedCounter

      public static void resetEmbedCounter()
      Reset the embed file sequence. Called at suite start so embed file names (e.g. 001_screenshot.png) restart from 1 for each run instead of accumulating across runs in the same JVM.

    • write

      public static void write(SuiteResult result, Path outputDir, String env)
      Generate HTML reports from a SuiteResult. This is the backward-compatible entry point for direct invocation.
      Parameters:
      result - the suite result to render
      outputDir - the directory to write reports
      env - the karate environment (may be null)

    • writeFeatureHtml

      public static void writeFeatureHtml(FeatureResult result, Path outputDir) throws IOException
      Write a single feature HTML report. Used by HtmlReportListener for async feature HTML generation.
      Parameters:
      result - the feature result to render
      outputDir - the root output directory (features/ subdirectory will be used)
      Throws:
      IOException

    • writeFeatureHtml

      public static void writeFeatureHtml(FeatureResult result, Path outputDir, Map<String,ReportAssets> reportAssets) throws IOException
      Throws:
      IOException

    • prepareFeatureData

      public static Map<String,Object> prepareFeatureData(FeatureResult result, Path outputDir) throws IOException
      Extract everything the feature page needs from a live FeatureResult.

      Split out from the render so a caller can do this synchronously, while the feature result is still whole, and defer only templating and IO. That ordering is what lets a suite release the nested karate.call() result trees as soon as a feature completes: everything the report needs has already been copied out. Do the extraction late — on a background thread, say — and the report silently loses its nested step detail.

      Throws:
      IOException

    • renderFeatureHtml

      public static void renderFeatureHtml(Map<String,Object> featureData, Path outputDir, Map<String,ReportAssets> reportAssets) throws IOException
      Template + IO only. Safe to run after the source FeatureResult has been released.
      Throws:
      IOException

    • externalizeEmbeds

      public static void externalizeEmbeds(FeatureResult result, Path outputDir)
      Externalize a feature result's inline-bytes embeds to <outputDir>/embeds/ and set each part's fileName, so EVERY downstream serializer — the JSONL event stream and the HTML data JSON — references the file rather than inlining base64 (large screenshots stay on disk, the report still works off a folder / file://). Called from the FEATURE_EXIT seam (Suite.fireEvent) before any listener serializes the result; idempotent (a part with a fileName is skipped), so the HTML writer's later pass numbers each embed exactly once. Best-effort — a write failure never breaks the run. JSON evidence stays inline (see writeEmbedFile(io.karatelabs.core.StepResult.Embed, java.nio.file.Path)).

    • writeSummaryPages

      public static void writeSummaryPages(List<Map<String,Object>> features, SuiteResult result, Path outputDir, String env) throws IOException
      Write summary pages (summary, index) from feature maps. Used by HtmlReportListener at suite end.
      Parameters:
      features - the collected feature maps (from FeatureResult.toJson())
      result - the suite result
      outputDir - the root output directory
      env - the karate environment (may be null)
      Throws:
      IOException

    • writeSummaryPages

      public static void writeSummaryPages(List<Map<String,Object>> features, SuiteResult result, Path outputDir, String env, Map<String,ReportAssets> reportAssets) throws IOException
      Throws:
      IOException

    • writeSummaryPages

      public static void writeSummaryPages(List<Map<String,Object>> features, SuiteResult result, Path outputDir, String env, Map<String,ReportAssets> reportAssets, List<Map<String,Object>> summaryCards) throws IOException
      Throws:
      IOException

    • copyStaticResources

      public static void copyStaticResources(Path resDir) throws IOException
      Copy static resources (CSS, JS, images) to the res directory. Made public for use by HtmlReportListener.
      Parameters:
      resDir - the res directory to copy resources to
      Throws:
      IOException

    • writeTimelineHtml

      public static void writeTimelineHtml(List<Map<String,Object>> features, SuiteResult result, Path outputDir, String env, int threadCount) throws IOException
      Write the timeline HTML page showing scenario execution across threads. Used by HtmlReportListener at suite end.
      Parameters:
      features - the collected feature maps (from FeatureResult.toMap())
      result - the suite result
      outputDir - the root output directory
      env - the karate environment (may be null)
      threadCount - the number of threads used for parallel execution
      Throws:
      IOException

    • writeTimelineHtml

      public static void writeTimelineHtml(List<Map<String,Object>> features, SuiteResult result, Path outputDir, String env, int threadCount, Map<String,ReportAssets> reportAssets) throws IOException
      Throws:
      IOException