Use Doxygen to generate the API documentation. (#1558)

* Integrated Doxygen documentation into Sphinx

Signed-off-by: lns <matzeton@googlemail.com>

.github/workflows/build.yml

@@ -34,7 +34,7 @@ jobs:
           ./tests/do-dga.sh
       - name: Generate Coverage Report
         run: |
-          mkdir -p coverage_report/ndpi_coverage_report
+          mkdir -vp coverage_report/ndpi_coverage_report
           lcov --directory . --capture --output-file lcov.info
           genhtml -o coverage_report/ndpi_coverage_report lcov.info
       - uses: actions/upload-artifact@v2
@@ -75,6 +75,39 @@ jobs:
           cd python
           python tests.py
 
+  documentation:
+    name: Documentation (ubuntu-latest)
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+        with:
+          fetch-depth: 0
+      - name: Set up Python 3.9
+        uses: actions/setup-python@v2
+        with:
+          python-version: "3.9"
+      - name: Install Ubuntu Prerequisites
+        run: |
+          sudo apt-get update
+          sudo apt-get install autoconf automake libtool pkg-config gettext flex bison doxygen
+      - name: Configure nDPI library
+        run: |
+          ./autogen.sh --with-only-libndpi
+      - name: Generate Documentation
+        run: |
+          cd doc
+          pip install --upgrade pip
+          pip install -r requirements.txt
+          make html
+          cd ..
+          mkdir -vp doc/_build/ndpi-documentation-upload/ndpi-documentation
+          mv -v doc/_build/html doc/_build/ndpi-documentation-upload/ndpi-documentation/html
+      - uses: actions/upload-artifact@v2
+        with:
+          name: ndpi-documentation
+          path: doc/_build/ndpi-documentation-upload
+          retention-days: 7
+
   test-scripts:
     name: Test Utils (ubuntu-latest)
     runs-on: ubuntu-latest
@@ -334,12 +367,6 @@ jobs:
         run: |
           make dist
           ./utils/verify_dist_tarball.sh
-      - name: Generate documentation
-        if: startsWith(matrix.os, 'ubuntu-latest') && startsWith(matrix.arch, 'x86_64')
-        run: |
-          pip3 install --user sphinxcontrib.swaggerdoc
-          make -C doc text
-          make -C doc html
       - name: Build nDPI [Mingw-w64] (runs only on ubuntu jobs)
         if: startsWith(matrix.os, 'ubuntu') && startsWith(matrix.arch, 'x86_64')
         run: |