Added ability to log out missing translations (#8477)

src/Orchard.Web/Config/log4net.config

@@ -34,6 +34,13 @@
         <priority value="WARN" />
     </logger>
 
+    <logger name="Orchard.Localization.Services.DefaultLocalizedStringManager">
+        <!-- Setting priority higher than INFO will prevent stuff being added to this logger 
+          Because in code this is filled by a Logger.Information -->
+        <priority value="OFF" />
+        <appender-ref ref="localization-file" />
+    </logger>
+
     <logger name="NHibernate.Cache">
         <!-- This source is very verbose - setting priority here to avoid flooding trace if root priority is lowered. -->
         <priority value="ERROR" />
@@ -104,4 +111,25 @@
         </layout>
     </appender>
 
+    <appender name="localization-file" type="Orchard.Logging.OrchardFileAppender">
+        <file value="App_Data/Logs/orchard-localization" />
+        <appendToFile value="true" />
+        <!-- Allow extended character sets (e.g. Chinese, Russian...) -->
+        <encoding value="utf-8" />
+        <!-- Immediate flush on error log, to avoid data loss with sudden termination. -->
+        <immediateFlush value="true" />
+        <staticLogFileName value="false" />
+        <rollingStyle value="Date" />
+        <datepattern value="-yyyy.MM.dd'.log'" />
+        <!-- Prevents Orchard.exe from displaying locking debug messages. -->
+        <lockingModel type="log4net.Appender.FileAppender+MinimalLock" />
+        <!-- Only add to this log the information about strings to localize -->
+        <filter type="log4net.Filter.StringMatchFilter">
+            <stringToMatch value="##CULTURE##" />
+        </filter>
+        <filter type="log4net.Filter.DenyAllFilter" />
+        <layout type="log4net.Layout.PatternLayout">
+            <conversionPattern value="%date %logger - %P{Tenant} - %level% [ExecutionId=%P{ExecutionId}]%newline[%P{Url}]%newline%message%newline " />
+        </layout>
+    </appender>
 </log4net>

src/Orchard/Localization/Services/DefaultLocalizedStringManager.cs

@@ -1,15 +1,14 @@
 using System.Collections.Generic;
 using System.Globalization;
+using System.Linq;
+using System.Text;
 using Orchard.Caching;
 using Orchard.Environment.Configuration;
+using Orchard.Environment.Descriptor.Models;
 using Orchard.Environment.Extensions;
 using Orchard.Environment.Extensions.Models;
 using Orchard.FileSystems.WebSite;
 using Orchard.Logging;
-using Orchard.Environment.Descriptor.Models;
-using System.Linq;
-using System.Collections;
-using System;
 
 namespace Orchard.Localization.Services {
     public class DefaultLocalizedStringManager : ILocalizedStringManager {
@@ -46,12 +45,30 @@ namespace Orchard.Localization.Services {
             Logger = NullLogger.Instance;
         }
 
-        ILogger Logger { get; set; }
+        public ILogger Logger { get; set; }
         public bool DisableMonitoring { get; set; }
 
         public FormatForScope GetLocalizedString(IEnumerable<string> scopes, string text, string cultureName) {
             var result = InnerGetLocalizedString(scopes, text, cultureName);
             if (result == null) {
+                /*
+                 * Log out messages that look like what we would have in the .po files
+                 * Prepend that with a line telling the target culture for which the localization is missing
+                msgctxt "Orchard.Users.Activities.CreateUserActivity"
+                msgid "InvalidPassword"
+                msgstr "**InvalidPassword**"
+                 */
+                var sb = new StringBuilder();
+                // The configured appender for the localizations file will only consider
+                // messages that contain "##CULTURE##"
+                sb.AppendLine("##CULTURE## " + cultureName);
+                // These three lines math those found in .po files.
+                sb.AppendLine("msgctxt \"" + scopes.FirstOrDefault() + "\"");
+                sb.AppendLine("msgid \"" + text + "\"");
+                sb.AppendLine("msgstr \"**" + text + "**\"");
+                // to enable/disable logging this information, search in log4net.config
+                // for the logger named Orchard.Localization.Services.DefaultLocalizedStringManager
+                Logger.Information(sb.ToString());
                 return new FormatForScope(text, scopes.FirstOrDefault());
             }
             return result;