/// <summary>
/// Try to deserialize the full resource represented by the specified <see cref="ArtifactSummary"/>.
/// </summary>
/// <param name="info">An <see cref="ArtifactSummary"/> instance.</param>
/// <typeparam name="T">The expected resource type.</typeparam>
/// <returns>A new instance of type <typeparamref name="T"/>, or <c>null</c>.</returns>
private static T getResourceFromScannedSource <T>(ArtifactSummary info)
where T : Resource
{
// File path of the containing resource file (could be a Bundle)
var path = info.Origin;
using (var navStream = DefaultNavigatorStreamFactory.Create(path))
{
// TODO: Handle exceptions & null return values
// e.g. file may have been deleted/renamed since last scan
// Advance stream to the target resource (e.g. specific Bundle entry)
if (navStream != null && navStream.Seek(info.Position))
{
// Create navigator for the target resource
var nav = navStream.Current;
if (nav != null)
{
// Parse target resource from navigator
var parser = new BaseFhirParser();
var result = parser.Parse <T>(nav);
if (result != null)
{
// Add origin annotation
result.SetOrigin(info.Origin);
return(result);
}
}
}
return(null);
}
}
/// <summary>
/// Generate a list of artifact summary information for a resource file on disk,
/// using the specified list of <see cref="ArtifactSummaryHarvester"/> instances.
/// <para>
/// If the target resource represents a <see cref="Bundle"/> instance, then the generator
/// returns a list of summaries for all resource entries contained in the bundle.
/// </para>
/// </summary>
/// <param name="filePath">The file path of the target artifact (or the containing Bundle).</param>
/// <param name="harvesters">
/// A list of <see cref="ArtifactSummaryHarvester"/> delegates that the
/// generator calls to harvest summary information from each artifact.
/// If the harvester list equals <c>null</c> or empty, then the generator will
/// harvest only the common default summary properties.
/// </param>
/// <returns>A list of new <see cref="ArtifactSummary"/> instances.</returns>
/// <remarks>
/// The generator catches all runtime exceptions that occur during harvesting and returns
/// them as <see cref="ArtifactSummary"/> instances with <see cref="ArtifactSummary.IsFaulted"/>
/// equal to <c>true</c> and <see cref="ArtifactSummary.Error"/> returning the exception.
/// </remarks>
public List <ArtifactSummary> Generate(
string filePath,
params ArtifactSummaryHarvester[] harvesters)
{
List <ArtifactSummary> result = null;
// Try to create navigator stream factory
// May fail if the specified input is invalid => return error summary
INavigatorStream navStream = null;
try
{
// Get some source file properties
var fi = new FileInfo(filePath);
// Local helper method to initialize origin-specific summary properties
// All resources from common origin share common property values
void InitializeSummaryFromOrigin(ArtifactSummaryPropertyBag properties)
{
properties.SetOrigin(filePath);
properties.SetFileSize(fi.Length);
// implicit conversion to DateTimeOffet. This is allowed, because LastWriteTimeUtc is of DateTimeKind.Utc
properties.SetLastModified(fi.LastWriteTimeUtc);
switch (fi.Extension)
{
case FhirFileFormats.XmlFileExtension:
properties.SetSerializationFormat(FhirSerializationFormats.Xml);
break;
case FhirFileFormats.JsonFileExtension:
properties.SetSerializationFormat(FhirSerializationFormats.Json);
break;
}
}
// Factory returns null for unknown file formats
navStream = DefaultNavigatorStreamFactory.Create(filePath);
result = Generate(navStream, InitializeSummaryFromOrigin, harvesters);
}
catch (Exception ex)
{
result = new List <ArtifactSummary>
{
ArtifactSummary.FromException(ex, filePath)
};
}
return(result);
}
/// <summary>
/// Generate a list of artifact summary information for a resource file on disk,
/// using the specified list of <see cref="ArtifactSummaryHarvester"/> instances.
/// <para>
/// If the target resource represents a <see cref="Bundle"/> instance, then the generator
/// returns a list of summaries for all resource entries contained in the bundle.
/// </para>
/// </summary>
/// <param name="origin">The file path of the target artifact (or the containing Bundle).</param>
/// <param name="harvesters">
/// A list of <see cref="ArtifactSummaryHarvester"/> delegates that the
/// generator calls to harvest summary information from each artifact.
/// If the harvester list equals <c>null</c> or empty, then the generator will
/// harvest only the common default summary properties.
/// </param>
/// <returns>A list of new <see cref="ArtifactSummary"/> instances.</returns>
/// <remarks>
/// The generator catches all runtime exceptions that occur during harvesting and returns
/// them as <see cref="ArtifactSummary"/> instances with <see cref="ArtifactSummary.IsFaulted"/>
/// equal to <c>true</c> and <see cref="ArtifactSummary.Error"/> returning the exception.
/// </remarks>
public static List <ArtifactSummary> Generate(
string origin,
params ArtifactSummaryHarvester[] harvesters)
{
List <ArtifactSummary> result = null;
// Try to create navigator stream factory
// May fail if the specified input is invalid => return error summary
INavigatorStream navStream = null;
try
{
navStream = DefaultNavigatorStreamFactory.Create(origin);
// Factory returns null for unknown file formats
if (navStream != null)
{
// Get some source file properties
var fi = new FileInfo(origin);
// Resources from same origin share a common serialization format
string format =
fi.Extension == FhirFileFormats.XmlFileExtension ? FhirSerializationFormats.Xml
: fi.Extension == FhirFileFormats.JsonFileExtension ? FhirSerializationFormats.Json
: null;
// Local helper method to initialize specific summary properties
void InitializeSummaryFromOrigin(ArtifactSummaryPropertyBag properties)
{
properties.SetOrigin(origin);
properties.SetFileSize(fi.Length);
properties.SetLastModified(fi.LastWriteTimeUtc);
properties.SetSerializationFormat(format);
}
result = Generate(navStream, InitializeSummaryFromOrigin, harvesters);
}
}
catch (Exception ex)
{
result = new List <ArtifactSummary>
{
ArtifactSummary.FromException(ex, origin)
};
}
return(result);
}
/// <summary>Returns <c>null</c> if the specified <paramref name="summary"/> equals <c>null</c>.</summary>
T loadResourceInternal <T>(ArtifactSummary summary) where T : Resource
{
if (summary == null)
{
return(null);
}
// File path of the containing resource file (could be a Bundle)
var origin = summary.Origin;
if (string.IsNullOrEmpty(origin))
{
throw Error.Argument($"Cannot load resource from summary. The {nameof(ArtifactSummary.Origin)} information is empty or missing.");
}
var pos = summary.Position;
if (string.IsNullOrEmpty(pos))
{
throw Error.Argument($"Cannot load resource from summary. The {nameof(ArtifactSummary.Position)} information is empty or missing.");
}
T result = null;
using (var navStream = DefaultNavigatorStreamFactory.Create(origin))
{
// Handle exceptions & null return values?
// e.g. file may have been deleted/renamed since last scan
// Advance stream to the target resource (e.g. specific Bundle entry)
if (navStream != null && navStream.Seek(pos))
{
// Create navigator for the target resource
var nav = navStream.Current;
if (nav != null)
{
// Parse target resource from navigator
var parser = new BaseFhirParser();
result = parser.Parse <T>(nav);
// Add origin annotation
result?.SetOrigin(origin);
}
}
}
return(result);
}
/// <summary>Generate a list of artifact summary information from an <see cref="INavigatorStream"/> instance.</summary>
/// <param name="origin">The original location of the target artifact (or the containing Bundle).</param>
/// <param name="harvesters">
/// An optional list of <see cref="ArtifactSummaryHarvester"/> delegates that the generator will call
/// instead of the default harvesters to harvest summary information from an artifact.
/// </param>
/// <returns>A list of new <see cref="ArtifactSummary"/> instances.</returns>
/// <remarks>
/// For each artifact, the generator executes all (default or specified) harvester delegates
/// in the specified order. When a delegate returns <c>true</c> to signal that harvesting has
/// finished, the generator will not call any of the remaining delegates and immediately
/// proceed to create the final <see cref="ArtifactSummary"/> return value.
/// <para>
/// By default, if the <paramref name="harvesters"/> parameter value is null or empty, the
/// <see cref="ArtifactSummaryGenerator"/> calls the built-in default harvesters
/// as specified by <see cref="ArtifactSummaryGenerator.DefaultHarvesters"/>.
/// However if the caller specifies one or more harvester delegates, then the summary
/// generator calls only the provided delegates, in the specified order.
/// A custom delegate array may include one or more of the default harvesters.
/// </para>
/// <para>
/// The generator catches all runtime exceptions that occur during harvesting and returns
/// them as <see cref="ArtifactSummary"/> instances with <see cref="ArtifactSummary.IsFaulted"/>
/// equal to <c>true</c> and <see cref="ArtifactSummary.Error"/> returning the exception.
/// </para>
/// </remarks>
public static List <ArtifactSummary> Generate(
string origin,
params ArtifactSummaryHarvester[] harvesters)
{
var result = new List <ArtifactSummary>();
// In case of error, return completed summaries and error info
INavigatorStream navStream = null;
try
{
// Call default navigator factory
navStream = DefaultNavigatorStreamFactory.Create(origin);
// Get some source file properties
var fi = new FileInfo(origin);
// Factory returns null for unknown file formats
if (navStream == null)
{
return(result);
}
// Run default or specified (custom) harvesters
if (harvesters == null || harvesters.Length == 0)
{
harvesters = DefaultHarvesters;
}
while (navStream.MoveNext())
{
var current = navStream.Current;
if (current != null)
{
var properties = new ArtifactSummaryPropertyBag();
// Initialize default summary information
// Note: not exposed by IElementNavigator, cannot use harvester
properties.SetOrigin(origin);
properties.SetFileSize(fi.Length);
properties.SetLastModified(fi.LastWriteTimeUtc);
properties.SetPosition(navStream.Position);
properties.SetTypeName(current.Type);
properties.SetResourceUri(navStream.Position);
var summary = generate(properties, current, harvesters);
result.Add(summary);
}
}
}
// TODO Catch specific exceptions
// catch (System.IO.FileNotFoundException)
// catch (UnauthorizedAccessException)
// catch (System.Security.SecurityException)
// catch (FormatException)
catch (Exception ex)
{
result.Add(ArtifactSummary.FromException(ex, origin));
}
finally
{
navStream?.Dispose();
}
return(result);
}
