Merge pull request #7 from cajuncoding/feature/add_support_to_load_accessibility_from_xml_or_az_func_config

Feature/add support to load accessibility from xml or az func config

Author: cajuncoding

apachefop-serverless-az-func/.vscode/settings.json

@@ -7,7 +7,9 @@
     "java.configuration.updateBuildConfiguration": "automatic",
     "maven.view": "hierarchical",
     "cSpell.words": [
+        "apachefop",
         "Gzipped",
+        "Keepin",
         "xslfo"
     ]
 }

apachefop-serverless-az-func/host.json

@@ -1,7 +1,7 @@
 {
-  "version": "2.0",
-  "extensionBundle": {
-    "id": "Microsoft.Azure.Functions.ExtensionBundle",
-    "version": "[1.*, 2.0.0)"
-  } 
+  "version": "2.0"//,
+  // "extensionBundle": {
+  //   "id": "Microsoft.Azure.Functions.ExtensionBundle",
+  //   "version": "[1.*, 2.0.0)"
+  // } 
 }

apachefop-serverless-az-func/src/main/java/com/cajuncoding/apachefop/serverless/apachefop/ApacheFopRenderResult.java

@@ -7,7 +7,7 @@ public class ApacheFopRenderResult {
     private final ApacheFopEventListener eventListener;
 
     public ApacheFopRenderResult(byte[] pdfBytes, ApacheFopEventListener eventListener) {
-        this.pdfBytes = pdfBytes;
+        this.pdfBytes = pdfBytes != null ? pdfBytes : new byte[0];
         this.eventListener = eventListener;
     }
 

apachefop-serverless-az-func/src/main/java/com/cajuncoding/apachefop/serverless/apachefop/ApacheFopRenderer.java

@@ -3,6 +3,10 @@
 import com.cajuncoding.apachefop.serverless.config.ApacheFopServerlessConfig;
 import com.cajuncoding.apachefop.serverless.config.ApacheFopServerlessConstants;
 import com.cajuncoding.apachefop.serverless.utils.ResourceUtils;
+import com.cajuncoding.apachefop.serverless.utils.XPathUtils;
+
+import org.apache.commons.io.IOUtils;
+import org.apache.commons.lang3.StringUtils;
 import org.apache.fop.apps.*;
 import org.apache.fop.configuration.ConfigurationException;
 import org.apache.fop.configuration.DefaultConfigurationBuilder;
@@ -11,6 +15,7 @@
 import javax.xml.transform.sax.SAXResult;
 import javax.xml.transform.stream.StreamSource;
 import java.io.*;
+import java.nio.charset.StandardCharsets;
 import java.text.MessageFormat;
 import java.util.logging.Logger;
 import java.util.zip.GZIPOutputStream;
@@ -93,23 +98,32 @@ protected synchronized void initApacheFopFactorySafely() {
             var configFilePath = ApacheFopServerlessConstants.ConfigXmlResourceName;
             FopFactory newFopFactory = null;
 
-            try (var configStream = ResourceUtils.loadResourceAsStream(configFilePath);) {
-                if (configStream != null) {
+            try {
+                String configXmlText = ResourceUtils.loadResourceAsString(configFilePath);
+                if (StringUtils.isNotBlank(configXmlText)) {
 
                     //When Debugging log the full Configuration file...
                     if(this.apacheFopConfig.isDebuggingEnabled()) {
-                        var configFileXmlText =ResourceUtils.loadResourceAsString(configFilePath);
-                        LogMessage("[DEBUG] ApacheFOP Configuration Xml:".concat(System.lineSeparator()).concat(configFileXmlText));
+                        LogMessage("[DEBUG] ApacheFOP Configuration Xml:".concat(System.lineSeparator()).concat(configXmlText));
                     }
 
                     //Attempt to initialize with Configuration loaded from Configuration XML Resource file...
-                    var cfgBuilder = new DefaultConfigurationBuilder();
-                    var cfg = cfgBuilder.build(configStream);
-
-                    var fopFactoryBuilder = new FopFactoryBuilder(baseUri, fopResourcesFileResolver).setConfiguration(cfg);
-
+                    //NOTE: FOP Factory requires a Stream so we have to initialize a new Stream for it to load from!
+                    FopFactoryBuilder fopFactoryBuilder;
+                    try(var configXmlStream = IOUtils.toInputStream(configXmlText, StandardCharsets.UTF_8)) {
+                        var cfgBuilder = new DefaultConfigurationBuilder();
+                        var cfg = cfgBuilder.build(configXmlStream);
+                        
+                        fopFactoryBuilder = new FopFactoryBuilder(baseUri, fopResourcesFileResolver).setConfiguration(cfg);
+                    }
                     //Ensure Accessibility is programmatically set (default configuration is false)...
-                    //fopFactoryBuilder.setAccessibility(this.apacheFopConfig.isAccessibilityPdfRenderingEnabled());
+                    //NOTE: There appears to be a bug in ApacheFOP code or documentation whereby it does not load the value from Xml as defined in the Docs!
+                    //      to work around this we read the value ourselves and also provide convenience support to simply set it in Azure Functions Configuration
+                    //      and if either configuration value is true then it will be enabled.
+                    //NOTE: The XPathUtils is null safe so any issues in loading/parsing will simply result in null or default values...
+                    var configXml = XPathUtils.fromXml(configXmlText);
+                    var isAccessibilityEnabledInXmlConfig = configXml.evalXPathAsBoolean("//fop/accessibility", false);
+                    fopFactoryBuilder.setAccessibility(this.apacheFopConfig.isAccessibilityPdfRenderingEnabled() || isAccessibilityEnabledInXmlConfig);
 
                     newFopFactory = fopFactoryBuilder.build();
                 }

apachefop-serverless-az-func/src/main/java/com/cajuncoding/apachefop/serverless/config/ApacheFopServerlessConfig.java

@@ -83,7 +83,7 @@ protected void readRequestQueryParamsConfig(Map<String, String> queryParams) {
 
         //Determine if Event Log Dump mode is enabled (vs PDF Binary return).
         this.eventLogDumpModeEnabled = BooleanUtils.toBoolean(
-                queryParams.getOrDefault(ApacheFopServerlessQueryParams.EventLogDump, null)
+            queryParams.getOrDefault(ApacheFopServerlessQueryParams.EventLogDump, null)
         );
 
     }

apachefop-serverless-az-func/src/main/java/com/cajuncoding/apachefop/serverless/utils/TextUtils.java

@@ -18,10 +18,6 @@ public static String getCurrentW3cDateTime() {
         return currentW3cDateTime;
     }
 
-    public static boolean isNullOrWhiteSpace(String value) {
-        return value == null || value.isBlank();
-    }
-
     /**
      * Truncates a string to the number of characters that fit in X bytes avoiding multi byte characters being cut in
      * half at the cut off point. Also handles surrogate pairs where 2 characters in the string is actually one literal

apachefop-serverless-az-func/src/main/java/com/cajuncoding/apachefop/serverless/utils/XPathUtils.java

@@ -0,0 +1,94 @@
+package com.cajuncoding.apachefop.serverless.utils;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.StringReader;
+import java.nio.charset.StandardCharsets;
+
+import javax.xml.parsers.DocumentBuilderFactory;
+import javax.xml.parsers.ParserConfigurationException;
+import javax.xml.xpath.XPath;
+import javax.xml.xpath.XPathExpressionException;
+import javax.xml.xpath.XPathFactory;
+
+import org.apache.commons.io.IOUtils;
+import org.w3c.dom.Document;
+import org.xml.sax.InputSource;
+import org.xml.sax.SAXException;
+
+public class XPathUtils {
+    
+    public static XPathUtils fromXml(String xmlContent)
+    {
+		try (var xmlContentStream = IOUtils.toInputStream(xmlContent, StandardCharsets.UTF_8)) {
+            return XPathUtils.fromXml(xmlContentStream);
+		} catch (IOException e) {
+            e.printStackTrace();
+        }
+
+        return new XPathUtils(null);
+    }
+
+    public static XPathUtils fromXml(InputStream xmlContentStream)
+    {
+        Document xmlDocument = null;
+        try {
+            xmlDocument = DocumentBuilderFactory.newInstance()
+                .newDocumentBuilder()
+                .parse(xmlContentStream);
+        } catch (SAXException | IOException | ParserConfigurationException e) {
+            e.printStackTrace();
+        }
+ 
+        return new XPathUtils(xmlDocument);
+    }
+
+    protected Document _xmlDoc;
+
+    public XPathUtils(Document xmlDoc)
+    {
+        _xmlDoc = xmlDoc;
+    }
+
+    public Document getXmlDocument() {
+        return _xmlDoc;
+    }
+
+    public <T>T evalXPath(String xpath, Class<T> classType) throws XPathExpressionException
+    {
+        return evalXPathInternal(xpath, classType);
+    }
+
+    public String evalXPathAsString(String xpath, String defaultIfNotFound) throws XPathExpressionException
+    {
+        try {
+            var result = evalXPathInternal(xpath, String.class);
+            return result != null ? result : defaultIfNotFound;
+        } catch (XPathExpressionException e) {
+            return defaultIfNotFound;
+        }
+    }
+
+    public boolean evalXPathAsBoolean(String xpath, boolean defaultIfNotFound)
+    {
+        try {
+            var result = evalXPathInternal(xpath, Boolean.class);
+            return (boolean)(result != null ? result : defaultIfNotFound);
+        } catch (XPathExpressionException e) {
+            return defaultIfNotFound;
+        }
+    }
+
+    public <T>T evalXPathInternal(String xpathCommand, Class<T> classType) throws XPathExpressionException
+    {
+        if(_xmlDoc == null)
+            return null;
+
+        XPath xpath = XPathFactory.newInstance().newXPath();
+        // //XPathExpression xpathExpression = xpathCompiler.compile(xpath);
+        // var result = xpathExpression.evaluate(_xmlDoc, returnType);
+        var result = xpath.evaluateExpression(xpathCommand, _xmlDoc, classType);
+        return result;
+    }
+}
+

apachefop-serverless-az-func/src/main/java/com/cajuncoding/apachefop/serverless/web/ApacheFopServerlessFunctionExecutor.java

@@ -92,6 +92,9 @@ protected <TRequest> HttpResponseMessage ExecuteRequestInternal(
         //Execute the transformation of the XSL-FO source content to Binary PDF format...
         var pdfRenderResult = fopHelper.renderPdfResult(xslFOBodyContent, config.isGzipResponseEnabled());
 
+        //Add some contextual Logging so we can know if the PDF bytes were rendered...
+        logger.info(MessageFormat.format("[SUCCESS] Successfully Rendered PDF with [{0}] bytes.", pdfRenderResult.getPdfBytes().length));
+
         //Render the PDF Response (or EventLog Dump if specified)...
         var response = config.isEventLogDumpModeEnabled()
                 ? responseBuilder.BuildEventLogDumpResponse(pdfRenderResult, config)

apachefop-serverless-az-func/src/main/java/com/cajuncoding/apachefop/serverless/web/SafeHeader.java

@@ -1,7 +1,8 @@
 package com.cajuncoding.apachefop.serverless.web;
 
 import com.cajuncoding.apachefop.serverless.http.HttpEncodings;
-import com.cajuncoding.apachefop.serverless.utils.TextUtils;
+
+import org.apache.commons.lang3.StringUtils;
 import org.apache.commons.text.StringEscapeUtils;
 
 import java.io.UnsupportedEncodingException;
@@ -19,10 +20,10 @@ public SafeHeader(String value, String encoding) throws UnsupportedEncodingExcep
     public String getValue() { return value; }
 
     protected String sanitizeTextForHttpHeader(String value, String encoding) throws UnsupportedEncodingException {
-        if(TextUtils.isNullOrWhiteSpace(value))
+        if(StringUtils.isBlank(value))
             return value;
 
-        if(encoding != null && encoding != HttpEncodings.IDENTITY_ENCODING)
+        if(StringUtils.isNotBlank(encoding) && !encoding.equalsIgnoreCase(HttpEncodings.IDENTITY_ENCODING))
             return value;
 
         //BBernard - 09/29/2021

apachefop-serverless-az-func/src/main/resources/apache-fop-config.xml

@@ -23,6 +23,9 @@
     <!-- All fonts information that has been gathered as a result of "directory" or "auto-detect" font configurations will be cached for future rendering runs.-->
     <use-cache>true</use-cache>
 
+    <!-- Enable Accessibility as noted in Apache FOP Docs; NOTE: There is a Bug where this isn't loaded but we now manually support this! -->
+    <accessibility>false</accessibility>
+
     <renderers>
         <renderer mime="application/pdf">
             <!-- Enable this to turn on Accessibility Support...