public IActionResult Run(
[HttpTrigger(AuthorizationLevel.Anonymous, "get", Route = null)] HttpRequest req,
ILogger log,
ExecutionContext context)
{
_config = FunctionsHelper.GetConfig(context);
_log = log;
string url = req.Query["url"];
if (!IsWhitelisted(url))
{
return(new NotFoundResult());
}
log.LogInformation($"Redirect: 302 {url}");
InsightsHelper.TrackEvents(_telemetryClient, "FunMetrics.Redirect", url, req);
return(new RedirectResult(url, false));
}
public async Task <IActionResult> Run(
[HttpTrigger(AuthorizationLevel.Anonymous, "get", "head", Route = null)] HttpRequest req,
ILogger log,
ExecutionContext context)
{
_config = FunctionsHelper.GetConfig(context);
string path = req.Query["path"];
log.LogInformation($"FunMetrics.Blob.Run: {req.Method} {path}");
if (string.IsNullOrWhiteSpace(path))
{
log.LogError("Querystring param \"path\" is null, empty or missing.");
return(new NotFoundResult());
}
if (path.StartsWith('/') || !path.Contains('/'))
{
log.LogError("Querystring param \"path\" is malformed. Must be a relative path to a blob file, with no leading \"/\".");
return(new NotFoundResult());
}
var uri = new Uri($"{CloudBlobClient.BaseUri}{path}");
log.LogInformation($"FunMetrics.Blob.Run: {req.Method} {uri}");
ICloudBlob blob;
try
{
blob = await CloudBlobClient.GetBlobReferenceFromServerAsync(uri);
}
catch (StorageException ex)
{
log.LogError(ex, "Returning 404 / Not found.");
return(new NotFoundResult());
}
if (req.Method == HttpMethods.Head)
{
// HEAD - Return empty body but with headers as if GET
req.HttpContext.Response.Headers["ETag"] = blob.Properties.ETag;
req.HttpContext.Response.ContentLength = blob.Properties.Length;
req.HttpContext.Response.ContentType = blob.Properties.ContentType;
if (blob.Properties.LastModified.HasValue)
{
req.HttpContext.Response.Headers["Last-Modified"] = blob.Properties.LastModified.Value.ToString("r");
}
return(new OkResult());
}
// GET - get blob and stream to client
InsightsHelper.TrackEvents(_telemetryClient, "FunMetrics.Blob", uri.ToString(), req);
Stream stream = null;
// try local cache
#if DEBUG
string cachePath = Path.GetTempPath();
#else
string cachePath = "D:\\Local\\";
#endif
string filePath = $"{cachePath}{path.Replace("/", "__")}";
bool cacheError = false;
if (File.Exists(filePath))
{
// retry three times
for (int i = 0; i < 3; i++)
{
// get from local cache
try
{
stream = new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.Read);
log.LogInformation($"FunMetrics.Blob.Run: Cache HIT {filePath}");
break;
}
catch (Exception ex)
{
log.LogError(ex, $"Could not open file \"{filePath}\" on attempt {i + 1}: {ex} {ex.Message}");
await Task.Delay(10);
}
cacheError = true;
}
}
if (stream == null)
{
// get from Blob
log.LogInformation($"FunMetrics.Blob.Run: Cache MISS {filePath}");
stream = new MemoryStream();
await blob.DownloadToStreamAsync(stream);
// don't try to save to cache if could not read from cache. File exists, was busy
if (!cacheError)
{
// save to cache
try
{
using (var fileStream = new FileStream(filePath, FileMode.CreateNew, FileAccess.Write))
{
stream.Seek(0, SeekOrigin.Begin);
stream.CopyTo(fileStream);
}
}
catch (Exception ex)
{
log.LogError(ex, $"Could not cache file \"{filePath}\".");
}
}
}
stream.Seek(0, SeekOrigin.Begin);
return(new FileStreamResult(stream, blob.Properties.ContentType)
{
EnableRangeProcessing = true,
EntityTag = new EntityTagHeaderValue(blob.Properties.ETag),
LastModified = blob.Properties.LastModified
});
}