feat: Add IsMeasurement option to Column attribute for dynamic measur…

…ement names in POCO classes (influxdata#240)

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ### Features
 1. [#239](https://github.com/influxdata/influxdb-client-csharp/pull/239): Add support for Asynchronous queries [LINQ]
+1. [#240](https://github.com/influxdata/influxdb-client-csharp/pull/240): Add IsMeasurement option to Column attribute for dynamic measurement names in POCO classes
 
 ## 3.0.0 [2021-09-17]
 

Client.Core.Test/AbstractTest.cs

@@ -114,13 +114,13 @@ private async Task InfluxDbRequest(HttpRequestMessage request)
  try
  {
  var response = await httpClient.SendAsync(request);
- Assert.IsTrue(response.IsSuccessStatusCode);
+ Assert.IsTrue(response.IsSuccessStatusCode, $"Failed to make HTTP request: {response.ReasonPhrase}");
 
  Thread.Sleep(DefaultInfluxDBSleep);
  }
- catch (Exception)
+ catch (Exception e)
  {
- Assert.Fail("Unexpected exception");
+ Assert.Fail("Unexpected exception: " + e);
  }
  }
  }

Client.Core/Attributes.cs

@@ -5,6 +5,7 @@ namespace InfluxDB.Client.Core
  /// <summary>
  /// The annotation is used for mapping POCO class into line protocol.
  /// </summary>
+ [AttributeUsage(AttributeTargets.Class)]
  public sealed class Measurement : Attribute
  {
  public string Name { get; }
@@ -18,10 +19,13 @@ public Measurement(string name)
  /// <summary>
  /// The annotation is used to customize bidirectional mapping between POCO and Flux query result or Line Protocol.
  /// </summary>
+ [AttributeUsage(AttributeTargets.Property)]
  public sealed class Column : Attribute
  {
  public string Name { get; }
 
+ public bool IsMeasurement { get; set; }
+
  public bool IsTag { get; set; }
 
  public bool IsTimestamp { get; set; }

Client.Core/Flux/Internal/AttributesCache.cs

@@ -30,7 +30,7 @@ public PropertyInfo[] GetProperties(Type type)
  }
 
  /// <summary>
- /// Get Mapping attribute for specified propery.
+ /// Get Mapping attribute for specified property.
  /// </summary>
  /// <param name="property">property of DomainObject</param>
  /// <returns>Property Attribute</returns>

Client.Core/Flux/Internal/FluxResultMapper.cs

@@ -69,6 +69,10 @@ internal object ToPoco(FluxRecord record, Type type)
  {
  var attribute = _attributesCache.GetAttribute(property);
 
+ if (attribute != null && attribute.IsMeasurement)
+ {
+ SetFieldValue(poco, property, record.GetMeasurement());
+ }
  if (attribute != null && attribute.IsTimestamp)
  {
  SetFieldValue(poco, property, record.GetTime());

Client.Linq/IMemberNameResolver.cs

@@ -33,6 +33,7 @@ public interface IMemberNameResolver
 
  public enum MemberType
  {
+ Measurement,
  Tag,
  Field,
  Timestamp,
@@ -52,6 +53,11 @@ public MemberType ResolveMemberType(MemberInfo memberInfo)
 
  if (attribute != null)
  {
+ if (attribute.IsMeasurement)
+ {
+ return MemberType.Measurement;
+ }
+
  if (attribute.IsTag)
  {
  return MemberType.Tag;

Client.Linq/Internal/Expressions/ColumnName.cs

@@ -18,6 +18,9 @@ public void AppendFlux(StringBuilder builder)
  {
  switch (_memberResolver.ResolveMemberType(_member))
  {
+ case MemberType.Measurement:
+ builder.Append("_measurement");
+ break;
  case MemberType.Timestamp:
  builder.Append("_time");
  break;

Client.Linq/Internal/Expressions/MeasurementColumnName.cs

@@ -0,0 +1,22 @@
+using System.Reflection;
+using System.Text;
+
+namespace InfluxDB.Client.Linq.Internal.Expressions
+{
+ internal class MeasurementColumnName : IExpressionPart
+ {
+ private readonly ColumnName _delegate;
+
+ internal MeasurementColumnName(MemberInfo member, IMemberNameResolver memberNameResolver)
+ {
+ _delegate = new ColumnName(member, memberNameResolver);
+ }
+
+ public void AppendFlux(StringBuilder builder)
+ {
+ builder.Append("r[\"");
+ _delegate.AppendFlux(builder);
+ builder.Append("\"]");
+ }
+ }
+}

Client.Linq/Internal/QueryExpressionTreeVisitor.cs

@@ -102,6 +102,9 @@ protected override Expression VisitMember(MemberExpression expression)
  {
  switch (_context.MemberResolver.ResolveMemberType(expression.Member))
  {
+ case MemberType.Measurement:
+ _expressionParts.Add(new MeasurementColumnName(expression.Member, _context.MemberResolver));
+ break;
  case MemberType.Timestamp:
  _expressionParts.Add(new TimeColumnName(expression.Member, _context.MemberResolver));
  break;

Client.Linq/Internal/QueryVisitor.cs

@@ -86,6 +86,7 @@ public override void VisitWhereClause(WhereClause whereClause, QueryModel queryM
  break;
  // Tag
  case TagColumnName _:
+ case MeasurementColumnName _:
  tagFilter.Add(expression);
  break;
  // Field

Client.Test/MeasurementMapperTest.cs

@@ -91,7 +91,36 @@ public void HeavyLoad()
 
  Assert.LessOrEqual(ts.Seconds, 10, $"Elapsed time: {elapsedTime}");
  }
-
+
+ [Test]
+ public void MeasurementProperty()
+ {
+ var poco = new MeasurementPropertyPoco
+ {
+ Measurement = "poco",
+ Tag = "tag val",
+ Value = 15.444,
+ ValueWithoutDefaultName = 20,
+ ValueWithEmptyName = 25d,
+ Timestamp = TimeSpan.FromDays(10)
+ };
+
+ var lineProtocol = _mapper.ToPoint(poco, WritePrecision.S).ToLineProtocol();
+
+ Assert.AreEqual("poco,tag=tag\\ val value=15.444,ValueWithEmptyName=25,ValueWithoutDefaultName=20i 864000", lineProtocol);
+ }
+
+ [Test]
+ public void MeasurementPropertyValidation()
+ {
+ var poco = new BadMeasurementAttributesPoco
+ {
+ Measurement = "poco"
+ };
+
+ Assert.Throws<InvalidOperationException>(() => _mapper.ToPoint(poco, WritePrecision.S));
+ }
+
  private class MyClass
  {
  public override string ToString()
@@ -118,5 +147,33 @@ private class Poco
  [Column(IsTimestamp = true)]
  public Object Timestamp { get; set; }
  }
+
+ private class MeasurementPropertyPoco
+ {
+ [Column(IsMeasurement = true)]
+ public string Measurement { get; set; }
+
+ [Column("tag", IsTag = true)]
+ public string Tag { get; set; }
+
+ [Column("value")]
+ public Object Value { get; set; }
+
+ [Column]
+ public int? ValueWithoutDefaultName { get; set; }
+
+ [Column("")]
+ public Double? ValueWithEmptyName { get; set; }
+
+ [Column(IsTimestamp = true)]
+ public Object Timestamp { get; set; }
+ }
+
+ [Measurement("poco")]
+ private class BadMeasurementAttributesPoco
+ {
+ [Column(IsMeasurement = true)]
+ public string Measurement { get; set; }
+ }
  }
 }

Client.Test/QueryApiTest.cs

@@ -79,6 +79,7 @@ public async Task GenericAndTypeofCalls()
  Assert.AreEqual(13.00, measurements[1].Value);
  Assert.IsAssignableFrom<SyncPoco>(measurementsTypeof[0]);
  var cast = measurementsTypeof.Cast<SyncPoco>().ToList();
+ Assert.AreEqual(measurements[0].Measurement, cast[0].Measurement);
  Assert.AreEqual(measurements[0].Timestamp, cast[0].Timestamp);
  Assert.AreEqual(12.25, cast[0].Value);
  Assert.AreEqual(13.00, cast[1].Value);
@@ -106,6 +107,8 @@ public async Task QueryAsyncEnumerable()
 
  private class SyncPoco
  {
+ [Column(IsMeasurement = true)] public string Measurement { get; set; }
+
  [Column("id", IsTag = true)] public string Tag { get; set; }
 
  [Column("_value")] public double Value { get; set; }

Client/Internal/MeasurementMapper.cs

@@ -35,18 +35,30 @@ internal PointData ToPoint<TM>(TM measurement, WritePrecision precision)
 
  var measurementType = measurement.GetType();
  CacheMeasurementClass(measurementType);
- 
+
  var measurementAttribute = (Measurement) measurementType.GetCustomAttribute(typeof(Measurement));
- if (measurementAttribute == null)
+ var measurementColumn = CACHE[measurementType.Name].SingleOrDefault(p => p.Column.IsMeasurement);
+
+ if (((measurementAttribute == null) ^ (measurementColumn == null)) == false)
  {
  throw new InvalidOperationException(
- $"Measurement {measurement} does not have a {typeof(Measurement)} attribute.");
+ $"Unable to determine Measurement for {measurement}. Does it have a {typeof(Measurement)} or IsMessage {typeof(Column)} attribute?");
  }
 
- var point = PointData.Measurement(measurementAttribute.Name);
+ string measurementName =
+ measurementAttribute == null
+ ? (string)measurementColumn.Property.GetValue(measurement)
+ : measurementAttribute.Name;
+
+ var point = PointData.Measurement(measurementName);
 
  foreach (var propertyInfo in CACHE[measurementType.Name])
  {
+ if (propertyInfo.Column.IsMeasurement)
+ {
+ continue;
+ }
+
  var value = propertyInfo.Property.GetValue(measurement);
  if (value == null)
  {