/// <summary>
/// Builds a <see cref="FallbackPolicy"/> which provides a fallback value if the main execution fails. Executes the main delegate asynchronously, but if this throws a handled exception or raises a handled result, returns <paramref name="fallbackValue"/>.
/// </summary>
/// <param name="policyBuilder">The policy builder.</param>
/// <param name="fallbackValue">The fallback <typeparamref name="TResult"/> value to provide.</param>
/// <returns>The policy instance.</returns>
public static FallbackPolicy <TResult> FallbackAsync <TResult>(this PolicyBuilder <TResult> policyBuilder, TResult fallbackValue)
{
Func <DelegateResult <TResult>, Task> doNothing = _ => TaskHelper.EmptyTask;
return(policyBuilder.FallbackAsync(
ct => TaskHelper.FromResult(fallbackValue),
doNothing
));
}
/// <summary>
/// Builds a <see cref="FallbackPolicy"/> which provides a fallback value if the main execution fails. Executes the main delegate asynchronously, but if this throws a handled exception or raises a handled result, first asynchronously calls <paramref name="onFallbackAsync"/> with details of the handled exception or result and the execution context; then returns <paramref name="fallbackValue"/>.
/// </summary>
/// <param name="policyBuilder">The policy builder.</param>
/// <param name="fallbackValue">The fallback <typeparamref name="TResult"/> value to provide.</param>
/// <param name="onFallbackAsync">The action to call asynchronously before invoking the fallback delegate.</param>
/// <exception cref="System.ArgumentNullException">onFallbackAsync</exception>
/// <returns>The policy instance.</returns>
public static FallbackPolicy <TResult> FallbackAsync <TResult>(this PolicyBuilder <TResult> policyBuilder, TResult fallbackValue, Func <DelegateResult <TResult>, Context, Task> onFallbackAsync)
{
if (onFallbackAsync == null)
{
throw new ArgumentNullException(nameof(onFallbackAsync));
}
return(policyBuilder.FallbackAsync(
ct => TaskHelper.FromResult(fallbackValue),
onFallbackAsync
));
}
/// <summary>
/// Builds an <see cref="AsyncFallbackPolicy{TResult}"/> which provides a fallback value if the main execution fails. Executes the main delegate asynchronously, but if this throws a handled exception or raises a handled result, first asynchronously calls <paramref name="onFallbackAsync"/> with details of the handled exception or result; then returns <paramref name="fallbackValue"/>.
/// </summary>
/// <param name="policyBuilder">The policy builder.</param>
/// <param name="fallbackValue">The fallback <typeparamref name="TResult"/> value to provide.</param>
/// <param name="onFallbackAsync">The action to call asynchronously before invoking the fallback delegate.</param>
/// <exception cref="ArgumentNullException">onFallbackAsync</exception>
/// <returns>The policy instance.</returns>
public static AsyncFallbackPolicy <TResult> FallbackAsync <TResult>(this PolicyBuilder <TResult> policyBuilder, TResult fallbackValue, Func <DelegateResult <TResult>, Task> onFallbackAsync)
{
if (onFallbackAsync == null)
{
throw new ArgumentNullException(nameof(onFallbackAsync));
}
return(policyBuilder.FallbackAsync(
(outcome, ctx, ct) => Task.FromResult(fallbackValue),
(outcome, context) => onFallbackAsync(outcome)
));
}
/// <summary>
/// Builds an <see cref="AsyncFallbackPolicy"/> which provides a fallback action if the main execution fails. Executes the main delegate asynchronously, but if this throws a handled exception, first asynchronously calls <paramref name="onFallbackAsync"/> with details of the handled exception and execution context; then asynchronously calls <paramref name="fallbackAction"/>.
/// </summary>
/// <param name="policyBuilder">The policy builder.</param>
/// <param name="fallbackAction">The fallback delegate.</param>
/// <param name="onFallbackAsync">The action to call asynchronously before invoking the fallback delegate.</param>
/// <exception cref="ArgumentNullException">fallbackAction</exception>
/// <exception cref="ArgumentNullException">onFallbackAsync</exception>
/// <returns>The policy instance.</returns>
public static AsyncFallbackPolicy FallbackAsync(this PolicyBuilder policyBuilder, Func <Context, CancellationToken, Task> fallbackAction, Func <Exception, Context, Task> onFallbackAsync)
{
if (fallbackAction == null)
{
throw new ArgumentNullException(nameof(fallbackAction));
}
if (onFallbackAsync == null)
{
throw new ArgumentNullException(nameof(onFallbackAsync));
}
return(policyBuilder.FallbackAsync((outcome, ctx, ct) => fallbackAction(ctx, ct), onFallbackAsync));
}
/// <summary>
/// Builds a <see cref="FallbackPolicy"/> which provides a fallback value if the main execution fails. Executes the main delegate asynchronously, but if this throws a handled exception or raises a handled result, first asynchronously calls <paramref name="onFallbackAsync"/> with details of the handled exception or result and the execution context; then asynchronously calls <paramref name="fallbackAction"/> and returns its result.
/// </summary>
/// <param name="policyBuilder">The policy builder.</param>
/// <param name="fallbackAction">The fallback delegate.</param>
/// <param name="onFallbackAsync">The action to call asynchronously before invoking the fallback delegate.</param>
/// <exception cref="System.ArgumentNullException">fallbackAction</exception>
/// <exception cref="System.ArgumentNullException">onFallbackAsync</exception>
/// <returns>The policy instance.</returns>
public static FallbackPolicy <TResult> FallbackAsync <TResult>(this PolicyBuilder <TResult> policyBuilder, Func <Context, CancellationToken, Task <TResult> > fallbackAction, Func <DelegateResult <TResult>, Context, Task> onFallbackAsync)
{
if (fallbackAction == null)
{
throw new ArgumentNullException(nameof(fallbackAction));
}
if (onFallbackAsync == null)
{
throw new ArgumentNullException(nameof(onFallbackAsync));
}
return(policyBuilder.FallbackAsync((outcome, ctx, ct) => fallbackAction(ctx, ct), onFallbackAsync));
}
/// <summary>
/// Builds a <see cref="FallbackPolicy"/> which provides a fallback action if the main execution fails. Executes the main delegate asynchronously, but if this throws a handled exception, asynchronously calls <paramref name="fallbackAction"/>.
/// </summary>
/// <param name="policyBuilder">The policy builder.</param>
/// <param name="fallbackAction">The fallback delegate.</param>
/// <exception cref="System.ArgumentNullException">fallbackAction</exception>
/// <returns>The policy instance.</returns>
public static FallbackPolicy FallbackAsync(this PolicyBuilder policyBuilder, Func <CancellationToken, Task> fallbackAction)
{
if (fallbackAction == null)
{
throw new ArgumentNullException(nameof(fallbackAction));
}
Func <Exception, Task> doNothing = _ => TaskHelper.EmptyTask;
return(policyBuilder.FallbackAsync(
fallbackAction,
doNothing
));
}
/// <summary>
/// Builds a <see cref="FallbackPolicy"/> which provides a fallback value if the main execution fails. Executes the main delegate asynchronously, but if this throws a handled exception or raises a handled result, asynchronously calls <paramref name="fallbackAction"/> and returns its result.
/// </summary>
/// <param name="policyBuilder">The policy builder.</param>
/// <param name="fallbackAction">The fallback delegate.</param>
/// <exception cref="System.ArgumentNullException">fallbackAction</exception>
/// <returns>The policy instance.</returns>
public static FallbackPolicy <TResult> FallbackAsync <TResult>(this PolicyBuilder <TResult> policyBuilder, Func <CancellationToken, Task <TResult> > fallbackAction)
{
if (fallbackAction == null)
{
throw new ArgumentNullException(nameof(fallbackAction));
}
Func <DelegateResult <TResult>, Task> doNothing = _ => TaskHelper.EmptyTask;
return(policyBuilder.FallbackAsync(
fallbackAction,
doNothing
));
}
