Add styles directory to WMS config (Unidata#470)

* Add wms styles directory to config

* Refactor to helper function to reduce duplication

docs/userguide/src/site/pages/thredds/ThreddsConfigRef.md

@@ -236,6 +236,7 @@ The following shows all the configuration options available in the WMS section o
   <allow>true</allow>
   <allowRemote>false</allowRemote>
   <paletteLocationDir>wmsPalettes</paletteLocationDir>
+  <stylesLocationDir>wmsStyles</stylesLocationDir>
   <maxImageWidth>2048</maxImageWidth>
   <maxImageHeight>2048</maxImageHeight>
 </WMS>
@@ -259,6 +260,13 @@ where they are contained.
   * More information on the format of palette files can also be found in the 
   [ncWMS documentation](https://reading-escience-centre.gitbooks.io/ncwms-user-guide/content/06-development.html#:~:text=To%20add%20new,in%20hexadecimal%20notation.).
   * If you created palette files for TDS 4.x and would like to use them in TDS 5.x, an open source tool named [Magic Palette Converter](https://github.com/billyz313/magic-palette-converter){:target="_blank"} for THREDDS is available to assist in the conversion (special thanks to [Billy Ashmall](https://github.com/Unidata/tds/discussions/346){:target="_blank"}!)
+* `stylesLocationDir`: optionally specify the location of the directory containing your own style files, by specifying the directory
+  where they are contained.
+  * If the directory location starts with a `/`, the path is absolute, otherwise it is relative to `${tds.content.root.path}/thredds/`.
+  * The default directory for custom styles files is `${tds.content.root.path}/thredds/wmsStyles`.
+  * If you don't specify a custom styles directory, or specify it incorrectly, the default directory will be used.
+  * More information on the format of style files can also be found in the
+    [ncWMS documentation](https://reading-escience-centre.gitbooks.io/ncwms-user-guide/content/06-development.html#styles).
 * `maxImageWidth`: the maximum image width in pixels that this WMS service will return.
 * `maxImageHeight`: the maximum image height in pixels that this WMS service will return.
 

tds/src/main/java/thredds/server/config/TdsConfigMapper.java

@@ -16,6 +16,7 @@
 import thredds.server.wms.ThreddsWmsCatalogue;
 import thredds.server.wms.config.WmsDetailedConfig;
 import uk.ac.rdg.resc.edal.graphics.utils.ColourPalette;
+import uk.ac.rdg.resc.edal.graphics.utils.SldTemplateStyleCatalogue;
 
 /**
  * Centralize the mapping of threddsConfig.xml configuration settings to the data objects used by
@@ -173,6 +174,7 @@ enum WmsConfigMappings {
     WMS_ALLOW("WMS.allow", null, "true"),
     WMS_ALLOW_REMOTE("WMS.allowRemote", null, "false"),
     WMS_PALETTE_LOCATION_DIR("WMS.paletteLocationDir", null, null),
+    WMS_STYLES_LOCATION_DIR("WMS.stylesLocationDir", null, null),
     WMS_MAXIMUM_IMAGE_WIDTH("WMS.maxImageWidth", null, "2048"),
     WMS_MAXIMUM_IMAGE_HEIGHT("WMS.maxImageHeight", null, "2048"),
     WMS_CONFIG_FILE("WMS.configFile", null, null);
@@ -200,14 +202,14 @@ String getValueFromThreddsConfig() {
 
     static void load(WmsConfigBean wmsConfig, TdsContext tdsContext) {
       final String defaultPaletteLocation = tdsContext.getThreddsDirectory() + "/wmsPalettes";
+      final String defaultStylesLocation = tdsContext.getThreddsDirectory() + "/wmsStyles";
       final String defaultWmsConfigFile = tdsContext.getThreddsDirectory() + "/wmsConfig.xml";
 
       wmsConfig.setAllow(Boolean.parseBoolean(WMS_ALLOW.getValueFromThreddsConfig()));
       wmsConfig.setAllowRemote(Boolean.parseBoolean(WMS_ALLOW_REMOTE.getValueFromThreddsConfig()));
 
-      String paletteLocation = WMS_PALETTE_LOCATION_DIR.getValueFromThreddsConfig();
-      if (paletteLocation == null)
-        paletteLocation = defaultPaletteLocation;
+      final String paletteLocation =
+          getValueFromThreddsConfigOrDefault(WMS_PALETTE_LOCATION_DIR, defaultPaletteLocation);
       wmsConfig.setPaletteLocationDir(paletteLocation);
       try {
         ColourPalette.addPaletteDirectory(new File(paletteLocation));
@@ -221,9 +223,17 @@ static void load(WmsConfigBean wmsConfig, TdsContext tdsContext) {
         }
       }
 
-      String wmsConfigFile = WMS_CONFIG_FILE.getValueFromThreddsConfig();
-      if (wmsConfigFile == null)
-        wmsConfigFile = defaultWmsConfigFile;
+      final String stylesLocation = getValueFromThreddsConfigOrDefault(WMS_STYLES_LOCATION_DIR, defaultStylesLocation);
+      wmsConfig.setStylesLocationDir(stylesLocation);
+      try {
+        SldTemplateStyleCatalogue.getStyleCatalogue().addStylesInDirectory(new File(stylesLocation));
+      } catch (FileNotFoundException e) {
+        if (!stylesLocation.equals(defaultStylesLocation)) {
+          startupLog.warn("Could not find custom styles directory {}", stylesLocation, e);
+        }
+      }
+
+      final String wmsConfigFile = getValueFromThreddsConfigOrDefault(WMS_CONFIG_FILE, defaultWmsConfigFile);
 
       WmsDetailedConfig wdc = WmsDetailedConfig.fromLocation(wmsConfigFile);
       if (wdc == null) {
@@ -261,6 +271,14 @@ static void load(WmsConfigBean wmsConfig, TdsContext tdsContext) {
     }
   }
 
+  private static String getValueFromThreddsConfigOrDefault(WmsConfigMappings property, String defaultValue) {
+    final String value = property.getValueFromThreddsConfig();
+    if (value == null) {
+      return defaultValue;
+    }
+    return value;
+  }
+
   enum TdsUpdateConfigMappings {
     TDSUPDAATE_LOGVERSIONINFO("TdsUpdateConfig.logVersionInfo", null, "true");
 

tds/src/main/java/thredds/server/config/WmsConfigBean.java

@@ -19,6 +19,7 @@ public class WmsConfigBean {
   private boolean allow;
   private boolean allowRemote;
   private String paletteLocationDir;
+  private String stylesLocationDir;
   private int maxImageWidth;
   private int maxImageHeight;
 
@@ -49,6 +50,14 @@ public void setPaletteLocationDir(String paletteLocationDir) {
     this.paletteLocationDir = paletteLocationDir;
   }
 
+  public String getStylesLocationDir() {
+    return stylesLocationDir;
+  }
+
+  public void setStylesLocationDir(String stylesLocationDir) {
+    this.stylesLocationDir = stylesLocationDir;
+  }
+
   public int getMaxImageWidth() {
     return maxImageWidth;
   }