const string kIntegrityAlgDef = HashUtil.kSha256; // for integrity
private static async Task <string> GetFileHash(string dstPath, string alg)
{
// compute a hash.
var hasher = new HashUtil(HashUtil.FindHasherByName(alg));
byte[] hashCode2 = await hasher.GetHashFileAsync(dstPath);
Debug.Assert(hashCode2 != null);
return(Convert.ToBase64String(hashCode2));
}
public async Task <CdnRet> SyncFile(string dstPath)
{
// Get a file from CDN if i don't already have it and check its integrity (if supplied)
// can throw.
byte[] hashCode1 = null;
HashUtil hasher = null;
var fi = new FileInfo(dstPath);
if (integrity == null)
{
// integrity doesn't exist so just check that the file exists locally.
if (fi.Exists && fi.Length > 0)
{
await UpdateIntegrity(dstPath); // suggest that we manually update integrity.
return(CdnRet.Valid); // it exists. good enough since we don't have integrity attribute.
}
// It doesn't exist locally. pull a local copy from CDN. No big deal.
}
else
{
// test local file integrity hash e.g. "sha256-", "sha384-"
int i = integrity.IndexOf(kIntegritySep);
if (i <= 0) // badly formed integrity ?? Fail ?
{
// This is bad !! i cant really fix this. fix it manually.
LoggerUtil.DebugException($"Bad CDN integrity format '{integrity}'", null);
return(CdnRet.Error);
}
hashCode1 = Convert.FromBase64String(integrity.Substring(i + 1));
hasher = new HashUtil(HashUtil.FindHasherByName(integrity));
if (fi.Exists)
{
// Does current file match integrity?
byte[] hashCode2 = await hasher.GetHashFileAsync(dstPath);
Debug.Assert(hashCode2 != null);
// string debugHash2 = Convert.ToBase64String(hashCode2);
if (ByteUtil.CompareBytes(hashCode1, hashCode2) == 0) // integrity match is good. Skip this.
{
return(CdnRet.Valid);
}
// local file DOES NOT MATCH integrity!!
// This really should never happen! Pull another file from the CDN and hope it matches.
}
}
if (this.CdnPath1 == null)
{
// this file has no CDN. So i can't do anything!
if (Minifier.IsMinName(dstPath) && await Minifier.CreateMinified(Minifier.GetNonMinName(dstPath), dstPath))
{
// Local only lacked a minified version. so i made one.
return(CdnRet.Updated);
}
LoggerUtil.DebugException($"No File ({integrity}) and No CDN path for '{name}'", null);
return(CdnRet.Error);
}
// Pull/Get the file from CDN.
LoggerUtil.DebugEntry($"Get '{this.CdnPath1}'");
var dl = new HttpDownloader(this.CdnPath1, dstPath);
// CDN can get "OperationCanceledException: The operation was canceled."
await dl.DownloadFileAsync(true); // Assume directory is created on demand.
if (integrity == null)
{
// destination file should exist now. Does it?
var fi2 = new FileInfo(dstPath);
if (!fi2.Exists || fi2.Length <= 0)
{
LoggerUtil.DebugException("CDN file size 0 for " + dstPath, null);
return(CdnRet.Error);
}
await UpdateIntegrity(dstPath);
}
else
{
// Now (re)test integrity for the file i just got!
hasher.Init();
byte[] hashCode2 = await hasher.GetHashFileAsync(dstPath);
if (ByteUtil.CompareBytes(hashCode1, hashCode2) != 0) // MUST match.
{
// This is BAD. It should never happen!
string debugHash2 = Convert.ToBase64String(hashCode2);
LoggerUtil.DebugException($"CDN integrity hash does not match for '{dstPath}'. should be integrity='{string.Concat(kIntegrityAlgDef, kIntegritySep, debugHash2)}'", null);
return(CdnRet.Error);
}
}
return(CdnRet.Updated); // got it.
}