/// <inheritdoc />
public Task <ModelBindingResult> BindModelAsync(ModelBindingContext bindingContext)
{
// This method is optimized to use cached tasks when possible and avoid allocating
// using Task.FromResult. If you need to make changes of this nature, profile
// allocations afterwards and look for Task<ModelBindingResult>.
var allowedBindingSource = bindingContext.BindingSource;
if (allowedBindingSource == null ||
!allowedBindingSource.CanAcceptDataFrom(BindingSource.Header))
{
// Headers are opt-in. This model either didn't specify [FromHeader] or specified something
// incompatible so let other binders run.
return(ModelBindingResult.NoResultAsync);
}
var request = bindingContext.OperationBindingContext.HttpContext.Request;
var modelMetadata = bindingContext.ModelMetadata;
// Property name can be null if the model metadata represents a type (rather than a property or parameter).
var headerName = bindingContext.FieldName;
object model = null;
if (bindingContext.ModelType == typeof(string))
{
string value = request.Headers[headerName];
if (value != null)
{
model = value;
}
}
else if (typeof(IEnumerable <string>).IsAssignableFrom(bindingContext.ModelType))
{
var values = request.Headers.GetCommaSeparatedValues(headerName);
if (values.Length > 0)
{
model = ModelBindingHelper.ConvertValuesToCollectionType(
bindingContext.ModelType,
values);
}
}
if (model == null)
{
return(ModelBindingResult.FailedAsync(bindingContext.ModelName));
}
else
{
bindingContext.ModelState.SetModelValue(
bindingContext.ModelName,
request.Headers.GetCommaSeparatedValues(headerName),
request.Headers[headerName]);
return(ModelBindingResult.SuccessAsync(bindingContext.ModelName, model));
}
}
/// <inheritdoc />
public Task <ModelBindingResult> BindModelAsync(ModelBindingContext bindingContext)
{
if (bindingContext == null)
{
throw new ArgumentNullException(nameof(bindingContext));
}
// This method is optimized to use cached tasks when possible and avoid allocating
// using Task.FromResult. If you need to make changes of this nature, profile
// allocations afterwards and look for Task<ModelBindingResult>.
// Check if this binder applies.
if (bindingContext.ModelType != typeof(byte[]))
{
return(ModelBindingResult.NoResultAsync);
}
// Check for missing data case 1: There was no <input ... /> element containing this data.
var valueProviderResult = bindingContext.ValueProvider.GetValue(bindingContext.ModelName);
if (valueProviderResult == ValueProviderResult.None)
{
return(ModelBindingResult.FailedAsync(bindingContext.ModelName));
}
bindingContext.ModelState.SetModelValue(bindingContext.ModelName, valueProviderResult);
// Check for missing data case 2: There was an <input ... /> element but it was left blank.
var value = valueProviderResult.FirstValue;
if (string.IsNullOrEmpty(value))
{
return(ModelBindingResult.FailedAsync(bindingContext.ModelName));
}
try
{
var model = Convert.FromBase64String(value);
return(ModelBindingResult.SuccessAsync(bindingContext.ModelName, model));
}
catch (Exception exception)
{
bindingContext.ModelState.TryAddModelError(
bindingContext.ModelName,
exception,
bindingContext.ModelMetadata);
}
// Matched the type (byte[]) only this binder supports. As in missing data cases, always tell the model
// binding system to skip other model binders i.e. return non-null.
return(ModelBindingResult.FailedAsync(bindingContext.ModelName));
}
public Task <ModelBindingResult> BindModelAsync(ModelBindingContext bindingContext)
{
// This method is optimized to use cached tasks when possible and avoid allocating
// using Task.FromResult. If you need to make changes of this nature, profile
// allocations afterwards and look for Task<ModelBindingResult>.
if (bindingContext.ModelMetadata.IsComplexType)
{
// this type cannot be converted
return(ModelBindingResult.NoResultAsync);
}
var valueProviderResult = bindingContext.ValueProvider.GetValue(bindingContext.ModelName);
if (valueProviderResult == ValueProviderResult.None)
{
// no entry
return(ModelBindingResult.NoResultAsync);
}
bindingContext.ModelState.SetModelValue(bindingContext.ModelName, valueProviderResult);
try
{
var model = valueProviderResult.ConvertTo(bindingContext.ModelType);
if (bindingContext.ModelType == typeof(string))
{
var modelAsString = model as string;
if (bindingContext.ModelMetadata.ConvertEmptyStringToNull &&
string.IsNullOrWhiteSpace(modelAsString))
{
model = null;
}
}
// When converting newModel a null value may indicate a failed conversion for an otherwise required
// model (can't set a ValueType to null). This detects if a null model value is acceptable given the
// current bindingContext. If not, an error is logged.
if (model == null && !bindingContext.ModelMetadata.IsReferenceOrNullableType)
{
bindingContext.ModelState.TryAddModelError(
bindingContext.ModelName,
bindingContext.ModelMetadata.ModelBindingMessageProvider.ValueMustNotBeNullAccessor(
valueProviderResult.ToString()));
return(ModelBindingResult.FailedAsync(bindingContext.ModelName));
}
else
{
return(ModelBindingResult.SuccessAsync(bindingContext.ModelName, model));
}
}
catch (Exception exception)
{
bindingContext.ModelState.TryAddModelError(
bindingContext.ModelName,
exception,
bindingContext.ModelMetadata);
// Were able to find a converter for the type but conversion failed.
// Tell the model binding system to skip other model binders.
return(ModelBindingResult.FailedAsync(bindingContext.ModelName));
}
}
