Improve errors on getting stream

2sic/2sxc#2521 2sic/2sxc#2522
2sic · Sep 17, 2021 · 62cd491 · 62cd491
1 parent 78fe605
commit 62cd491
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Showing 4 changed files with 49 additions and 5 deletions.
diff --git a/ToSic.Eav.DataSources/DataSources/App_OutBuilder.cs b/ToSic.Eav.DataSources/DataSources/App_OutBuilder.cs
@@ -77,7 +77,7 @@ private void CreateAppOutWithAllStreams()
                     () => new CacheInfoAppAndMore("AppTypeStream" + AppRootCacheKey.AppCacheKey(this), appState, $"Name={typeName}&Drafts={showDrafts}"),
                     this,
                     typeName,
-                    () => BuildTypeStream(upstreamDataSource, typeName)[Constants.DefaultStreamName].List.ToImmutableArray(),
+                    () => BuildTypeStream(upstreamDataSource, typeName).List /*[Constants.DefaultStreamName].List*/.ToImmutableArray(),
                     true);
                 _out.Add(typeName, deferredStream);
             }

diff --git a/ToSic.Eav.DataSources/DataSources/DataSourceBase_Connections.cs b/ToSic.Eav.DataSources/DataSources/DataSourceBase_Connections.cs
@@ -1,4 +1,5 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using ToSic.Eav.Data;
 using ToSic.Eav.Documentation;
 
@@ -19,10 +20,38 @@ public abstract partial class DataSourceBase
         public virtual IDictionary<string, IDataStream> Out { get; protected internal set; } = new StreamDictionary();
 
         /// <inheritdoc />
-        public IDataStream this[string outName] => Out[outName];
+        public IDataStream this[string outName] => GetStream(outName);
 
         /// <inheritdoc />
-        public IEnumerable<IEntity> List => Out[Constants.DefaultStreamName].List;
+        public IDataStream GetStream(string name = null, string noParameterOrder = Parameters.Protector, bool nullIfNotFound = false, bool emptyIfNotFound = false)
+        {
+            Parameters.ProtectAgainstMissingParameterNames(noParameterOrder, nameof(GetStream), $"{nameof(nullIfNotFound)}");
+
+            // Check if streamName was not provided
+            if (string.IsNullOrEmpty(name)) name = Constants.DefaultStreamName;
+
+            // Simple case - just get it
+            if (Out.ContainsKey(name)) return Out[name];
+
+            if (nullIfNotFound && emptyIfNotFound)
+                throw new ArgumentException($"You cannot set both {nameof(nullIfNotFound)} and {nameof(emptyIfNotFound)} to true");
+
+            // If null is preferred to an error, return this
+            if (nullIfNotFound) return null;
+
+            // If empty is preferred to an error, return this
+            if (emptyIfNotFound) return new DataStream(this, name, () => new List<IEntity>());
+
+            // Not found and no rule to handle it, throw error
+            throw new KeyNotFoundException(
+                $"Can't find Stream with the name '{name}'. This could be a typo. Otherwise we recommend that you use either " +
+                $"'{nameof(nullIfNotFound)}: true' (for null-checks or ?? chaining) " +
+                $"or '{nameof(emptyIfNotFound)}: true' (for situations where you just want to add LINQ statements"
+            );
+        }
+
+        /// <inheritdoc />
+        public IEnumerable<IEntity> List => GetStream().List; // Out[Constants.DefaultStreamName].List;
 
 
         #region various Attach-In commands

diff --git a/ToSic.Eav.DataSources/Interfaces/IDataSource.cs b/ToSic.Eav.DataSources/Interfaces/IDataSource.cs
@@ -33,6 +33,21 @@ public interface IDataSource: IDataPartShared, IAppIdentity, ICacheInfo, ICanPur
 		/// <exception cref="NullReferenceException">if the stream does not exist</exception>
 		IDataStream this[string outName] { get; }
 
+        /// <summary>
+        /// Gets the Out-Stream with specified Name and allowing some error handling if not found.
+        /// </summary>
+        /// <param name="name">The desired stream name. If empty, will default to the default stream.</param>
+        /// <param name="noParameterOrder">see [](xref:NetCode.Conventions.NamedParameters)</param>
+        /// <param name="nullIfNotFound">In case the stream <see cref="name"/> isn't found, will return null. Ideal for chaining with ??</param>
+        /// <param name="emptyIfNotFound">In case the stream <see cref="name"/> isn't found, will return an empty stream. Ideal for using LINQ directly.</param>
+        /// <returns>an <see cref="IDataStream"/> of the desired name</returns>
+        /// <exception cref="NullReferenceException">if the stream does not exist and <see cref="nullIfNotFound"/> is false</exception>
+        /// <remarks>
+        /// 1. Added in 2sxc 12.05
+        /// 1. for more in-depth checking if a stream exists, you can access the <see cref="Out"/> which is an IDictionary
+        /// </remarks>
+        IDataStream GetStream(string name = null, string noParameterOrder = Parameters.Protector, bool nullIfNotFound = false, bool emptyIfNotFound = false);
+
         /// <summary>
         /// The items in the data-source - to be exact, the ones in the Default stream.
         /// </summary>

diff --git a/ToSic.Eav.DataSources/Queries/QueryBuilder.cs b/ToSic.Eav.DataSources/Queries/QueryBuilder.cs
@@ -50,7 +50,7 @@ public QueryDefinition GetQueryDefinition(int appId, int queryEntityId)
             {
                 var app = _appStates.Identity(null, appId);
                 var source = _dataSourceFactory.GetPublishing(app);
-	            var appEntities = source[Constants.DefaultStreamName].List;
+                var appEntities = source.List; // [Constants.DefaultStreamName].List;
 
 	            // use findRepo, as it uses the cache, which gives the list of all items
 	            var dataQuery = appEntities.FindRepoId(queryEntityId);