--- a
+++ b/src/mediaserver/cdplugins/netfetch.h
@@ -0,0 +1,78 @@
+/* Copyright (C) 2017-2018 J.F.Dockes
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation; either version 2 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program; if not, write to the
+ *   Free Software Foundation, Inc.,
+ *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ */
+
+#ifndef _MEDIAFETCH_H_INCLUDED_
+#define _MEDIAFETCH_H_INCLUDED_
+
+#include "bufxchange.h"
+#include "abuffer.h"
+
+//
+// Wrapper for a network fetch
+//
+// The transfer is aborted when the object is deleted, with proper
+// cleanup.
+//
+// The end of transfer is marked by pushing an empty buffer on the queue
+//
+// All methods are supposedly thread-safe
+class NetFetch {
+public:
+    NetFetch() {}
+    virtual ~NetFetch() {}
+
+    virtual void setTimeout(int secs) = 0;
+    
+    /// Start the transfer to the output queue.
+    virtual bool start(BufXChange<ABuffer*> *queue, uint64_t offset = 0) = 0;
+
+    // Wait for headers. This allows, e.g. doing stuff depending on
+    // content-type before proceeding with the actual data
+    // transfer. May not work exactly the same depending on the
+    // underlaying implementation.
+    virtual bool waitForHeaders(int maxSecs = 0) = 0;
+    // Retrieve header value (after a successful waitForHeaders).
+    virtual bool headerValue(const std::string& nm, std::string& val) = 0;
+
+    // Check if the fetch is done and retrieve the results if it
+    // is. This does not wait, it returns false if the transfer is
+    // still running.
+    // The pointers can be set to zero if no value should be retrieved
+    enum FetchStatus {FETCH_OK=0, FETCH_RETRYABLE, FETCH_FATAL};
+    virtual bool fetchDone(FetchStatus *code, int *http_code) = 0;
+
+    /// Reset after transfer done, for retrying for exemple.
+    virtual void reset() = 0;
+
+    // Callbacks
+
+    // A function to create the first buffer (typically for prepending
+    // a wav header to a raw pcm stream. If set this is called from
+    // the first curl write callback, before processing the curl data,
+    // so this happens at a point where the client may have had a look
+    // at the headers).
+    virtual void setBuf1GenCB(std::function<bool(std::string& buf,void*,int)>) {
+    }
+    // Called when the network transfer is done
+    void setEOFetchCB(std::function<void(bool ok, u_int64_t count)>) {
+    }
+    // Called every time we get new data from the remote
+    void setFetchBytesCB(std::function<void(u_int64_t count)>) {
+    }
+};
+
+#endif /* _MEDIAFETCH_H_INCLUDED_ */