From d94b1d80d8326334d17f6a43061368e783b8e0aa Mon Sep 17 00:00:00 2001
From: David Kalnischkies <david@kalnischkies.de>
Date: Thu, 11 Aug 2016 18:24:35 +0200
Subject: don't sent Range requests if we know its not accepted

If the server told us in a previous request that it isn't supporting
Ranges with bytes via an Accept-Ranges header missing bytes, we don't
try to formulate requests using Ranges.
---
 methods/http.cc   |  2 +-
 methods/https.cc  | 15 ++++++++-------
 methods/server.cc | 10 ++++++++++
 methods/server.h  |  1 +
 4 files changed, 20 insertions(+), 8 deletions(-)

(limited to 'methods')

diff --git a/methods/http.cc b/methods/http.cc
index 8d34aa6e3..11136bb9a 100644
--- a/methods/http.cc
+++ b/methods/http.cc
@@ -906,7 +906,7 @@ void HttpMethod::SendReq(FetchItem *Itm)
 
    // Check for a partial file and send if-queries accordingly
    struct stat SBuf;
-   if (stat(Itm->DestFile.c_str(),&SBuf) >= 0 && SBuf.st_size > 0)
+   if (Server->RangesAllowed && stat(Itm->DestFile.c_str(),&SBuf) >= 0 && SBuf.st_size > 0)
       Req << "Range: bytes=" << std::to_string(SBuf.st_size) << "-\r\n"
 	 << "If-Range: " << TimeRFC1123(SBuf.st_mtime, false) << "\r\n";
    else if (Itm->LastModified != 0)
diff --git a/methods/https.cc b/methods/https.cc
index c86f9407e..b2d05136c 100644
--- a/methods/https.cc
+++ b/methods/https.cc
@@ -382,8 +382,15 @@ bool HttpsMethod::Fetch(FetchItem *Itm)
 	 headers = curl_slist_append(headers, "Accept: text/*");
    }
 
+   // go for it - if the file exists, append on it
+   File = new FileFd(Itm->DestFile, FileFd::WriteAny);
+   if (Server == nullptr || Server->Comp(Itm->Uri) == false)
+      Server = CreateServerState(Itm->Uri);
+   else
+      Server->Reset(false);
+
    // if we have the file send an if-range query with a range header
-   if (stat(Itm->DestFile.c_str(),&SBuf) >= 0 && SBuf.st_size > 0)
+   if (Server->RangesAllowed && stat(Itm->DestFile.c_str(),&SBuf) >= 0 && SBuf.st_size > 0)
    {
       std::string Buf;
       strprintf(Buf, "Range: bytes=%lli-", (long long) SBuf.st_size);
@@ -397,12 +404,6 @@ bool HttpsMethod::Fetch(FetchItem *Itm)
       curl_easy_setopt(curl, CURLOPT_TIMEVALUE, Itm->LastModified);
    }
 
-   // go for it - if the file exists, append on it
-   File = new FileFd(Itm->DestFile, FileFd::WriteAny);
-   if (Server == nullptr || Server->Comp(Itm->Uri) == false)
-      Server = CreateServerState(Itm->Uri);
-   else
-      Server->Reset(false);
    if (Server->InitHashes(Itm->ExpectedHashes) == false)
       return false;
 
diff --git a/methods/server.cc b/methods/server.cc
index d0b6ef3d7..aa1ee4754 100644
--- a/methods/server.cc
+++ b/methods/server.cc
@@ -227,6 +227,15 @@ bool ServerState::HeaderLine(string Line)
       return true;
    }
 
+   if (stringcasecmp(Tag, "Accept-Ranges:") == 0)
+   {
+      std::string ranges = ',' + Val + ',';
+      ranges.erase(std::remove(ranges.begin(), ranges.end(), ' '), ranges.end());
+      if (ranges.find(",bytes,") == std::string::npos)
+	 RangesAllowed = false;
+      return true;
+   }
+
    return true;
 }
 									/*}}}*/
@@ -252,6 +261,7 @@ void ServerState::Reset(bool const Everything)				/*{{{*/
    if (Everything)
    {
       Persistent = false; Pipeline = false; PipelineAllowed = true;
+      RangesAllowed = true;
    }
 }
 									/*}}}*/
diff --git a/methods/server.h b/methods/server.h
index 63acceae6..c3adba87a 100644
--- a/methods/server.h
+++ b/methods/server.h
@@ -51,6 +51,7 @@ struct ServerState
    enum {Header, Data} State;
    bool Persistent;
    bool PipelineAllowed;
+   bool RangesAllowed;
    std::string Location;
 
    // This is a Persistent attribute of the server itself.
-- 
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