added resource_api and rs-nogui-webui (requires libmicrohttpd, Html files are not included)

git-svn-id: http://svn.code.sf.net/p/retroshare/code/trunk@8047 b45a01b8-16f6-495d-af2f-9b41ad6348cc

libresapi/src/api/Pagination.h

@@ -0,0 +1,79 @@
+#pragma once
+
+#include "ApiTypes.h"
+
+namespace resource_api
+{
+
+// C must be a type with STL like iterator, a begin() and an end() method
+// additionally a function id() which gives a unique value for every container element
+// the type of the id should be string
+// the type returned by dereferencing the iterator should have a stream operator for StreamBase
+// the stream operator must not add an element "id", this is done by the pagination handler
+template<class C>
+void handlePaginationRequest(Request& req, Response& resp, const C& data)
+{
+    if(!req.isGet()){
+        resp.mDebug << "unsupported method. only GET is allowed." << std::endl;
+        resp.setFail();
+        return;
+    }
+    if(data.begin() == data.end()){
+        // set result type to list
+        resp.mDataStream.getStreamToMember();
+        resp.mDebug << "note: list is empty" << std::endl;
+        return;
+    }
+
+    std::string first;
+    std::string last;
+    req.mStream << makeKeyValueReference("first", first) << makeKeyValueReference("last", last);
+
+    C::iterator it_first = data.begin();
+    if(first != "begin")
+    {
+        while(it_first != data.end() && id(*it_first) != first)
+            it_first++;
+        if(it_first == data.end())
+        {
+            resp.setFail("Error: first id did not match any element");
+            return;
+        }
+    }
+
+    C::iterator it_last = data.begin();
+    if(last == "end")
+    {
+        it_last = data.end();
+    }
+    else
+    {
+        while(it_last != data.end() && id(*it_last) != last)
+            it_last++;
+        if(it_last == data.end())
+        {
+            resp.setFail("Error: last id did not match any element");
+            return;
+        }
+        ++it_last; // increment to get iterator to element after the last wanted element
+    }
+
+    int count = 0;
+    for(C::iterator it = it_first; it != it_last; ++it)
+    {
+        StreamBase& stream = resp.mDataStream.getStreamToMember();
+        stream << *it;
+        stream << makeKeyValue("id", id(*it));
+
+        // todo: also handle the case when the last element is specified and the first element is begin
+        // then want to return the elements near the specified element
+        count++;
+        if(count > 20){
+            resp.mDebug << "limited the number of returned items to 20" << std::endl;
+            break;
+        }
+    }
+    resp.setOk();
+}
+
+} // namespace resource_api