[REST] make selection of output-format mandatory, support dot url syntax

1. Remove the default format (binary) because `rest/block/<hash>/Hex` would end up delivering binary data.
2. List available formats when chosen format was not found (reduces need for documentation)
3. Change url syntax to dot extension like format chosing (like `rest/tx/<hash>.json`

src/rest.cpp

@@ -18,6 +18,7 @@ using namespace std;
 using namespace json_spirit;
 
 enum RetFormat {
+    RF_UNDEF,
     RF_BINARY,
     RF_HEX,
     RF_JSON,
@@ -25,14 +26,16 @@ enum RetFormat {
 
 static const struct {
     enum RetFormat rf;
-    const char *name;
+    const char* name;
 } rf_names[] = {
-    { RF_BINARY, "binary" },            // default, if match not found
-    { RF_HEX, "hex" },
-    { RF_JSON, "json" },
+      {RF_UNDEF, ""},
+      {RF_BINARY, "bin"},
+      {RF_HEX, "hex"},
+      {RF_JSON, "json"},
 };
 
-class RestErr {
+class RestErr
+{
 public:
     enum HTTPStatusCode status;
     string message;
@@ -49,15 +52,34 @@ static RestErr RESTERR(enum HTTPStatusCode status, string message)
     return re;
 }
 
-static enum RetFormat ParseDataFormat(const string& format)
+static enum RetFormat ParseDataFormat(vector<string>& params, const string strReq)
 {
-    for (unsigned int i = 0; i < ARRAYLEN(rf_names); i++)
-        if (format == rf_names[i].name)
-            return rf_names[i].rf;
+    boost::split(params, strReq, boost::is_any_of("."));
+    if (params.size() > 1) {
+        for (unsigned int i = 0; i < ARRAYLEN(rf_names); i++)
+            if (params[1] == rf_names[i].name)
+                return rf_names[i].rf;
+    }
 
     return rf_names[0].rf;
 }
 
+static string AvailableDataFormatsString()
+{
+    string formats = "";
+    for (unsigned int i = 0; i < ARRAYLEN(rf_names); i++)
+        if (strlen(rf_names[i].name) > 0) {
+            formats.append(".");
+            formats.append(rf_names[i].name);
+            formats.append(", ");
+        }
+
+    if (formats.length() > 0)
+        return formats.substr(0, formats.length() - 2);
+
+    return formats;
+}
+
 static bool ParseHashStr(const string& strReq, uint256& v)
 {
     if (!IsHex(strReq) || (strReq.size() != 64))
@@ -67,15 +89,13 @@ static bool ParseHashStr(const string& strReq, uint256& v)
     return true;
 }
 
-static bool rest_block(AcceptedConnection *conn,
+static bool rest_block(AcceptedConnection* conn,
                        string& strReq,
                        map<string, string>& mapHeaders,
                        bool fRun)
 {
     vector<string> params;
-    boost::split(params, strReq, boost::is_any_of("/"));
-
-    enum RetFormat rf = ParseDataFormat(params.size() > 1 ? params[1] : string(""));
+    enum RetFormat rf = ParseDataFormat(params, strReq);
 
     string hashStr = params[0];
     uint256 hash;
@@ -105,7 +125,7 @@ static bool rest_block(AcceptedConnection *conn,
     }
 
     case RF_HEX: {
-        string strHex = HexStr(ssBlock.begin(), ssBlock.end()) + "\n";;
+        string strHex = HexStr(ssBlock.begin(), ssBlock.end()) + "\n";
         conn->stream() << HTTPReply(HTTP_OK, strHex, fRun, false, "text/plain") << std::flush;
         return true;
     }
@@ -115,22 +135,24 @@ static bool rest_block(AcceptedConnection *conn,
         string strJSON = write_string(Value(objBlock), false) + "\n";
         conn->stream() << HTTPReply(HTTP_OK, strJSON, fRun) << std::flush;
         return true;
-     }
+    }
+
+    default: {
+        throw RESTERR(HTTP_NOT_FOUND, "output format not found (available: " + AvailableDataFormatsString() + ")");
+    }
     }
 
     // not reached
-    return true;     // continue to process further HTTP reqs on this cxn
+    return true; // continue to process further HTTP reqs on this cxn
 }
 
-static bool rest_tx(AcceptedConnection *conn,
+static bool rest_tx(AcceptedConnection* conn,
                     string& strReq,
                     map<string, string>& mapHeaders,
                     bool fRun)
 {
     vector<string> params;
-    boost::split(params, strReq, boost::is_any_of("/"));
-
-    enum RetFormat rf = ParseDataFormat(params.size() > 1 ? params[1] : string(""));
+    enum RetFormat rf = ParseDataFormat(params, strReq);
 
     string hashStr = params[0];
     uint256 hash;
@@ -153,7 +175,7 @@ static bool rest_tx(AcceptedConnection *conn,
     }
 
     case RF_HEX: {
-        string strHex = HexStr(ssTx.begin(), ssTx.end()) + "\n";;
+        string strHex = HexStr(ssTx.begin(), ssTx.end()) + "\n";
         conn->stream() << HTTPReply(HTTP_OK, strHex, fRun, false, "text/plain") << std::flush;
         return true;
     }
@@ -165,33 +187,37 @@ static bool rest_tx(AcceptedConnection *conn,
         conn->stream() << HTTPReply(HTTP_OK, strJSON, fRun) << std::flush;
         return true;
     }
+
+    default: {
+        throw RESTERR(HTTP_NOT_FOUND, "output format not found (available: " + AvailableDataFormatsString() + ")");
+    }
     }
 
     // not reached
-    return true;     // continue to process further HTTP reqs on this cxn
+    return true; // continue to process further HTTP reqs on this cxn
 }
 
 static const struct {
-    const char *prefix;
-    bool (*handler)(AcceptedConnection *conn,
+    const char* prefix;
+    bool (*handler)(AcceptedConnection* conn,
                     string& strURI,
                     map<string, string>& mapHeaders,
                     bool fRun);
 } uri_prefixes[] = {
-    { "/rest/tx/", rest_tx },
-    { "/rest/block/", rest_block },
+      {"/rest/tx/", rest_tx},
+      {"/rest/block/", rest_block},
 };
 
-bool HTTPReq_REST(AcceptedConnection *conn,
+bool HTTPReq_REST(AcceptedConnection* conn,
                   string& strURI,
                   map<string, string>& mapHeaders,
                   bool fRun)
 {
     try {
         std::string statusmessage;
-        if(RPCIsInWarmup(&statusmessage))
-            throw RESTERR(HTTP_SERVICE_UNAVAILABLE, "Service temporarily unavailable: "+statusmessage);
-        
+        if (RPCIsInWarmup(&statusmessage))
+            throw RESTERR(HTTP_SERVICE_UNAVAILABLE, "Service temporarily unavailable: " + statusmessage);
+
         for (unsigned int i = 0; i < ARRAYLEN(uri_prefixes); i++) {
             unsigned int plen = strlen(uri_prefixes[i].prefix);
             if (strURI.substr(0, plen) == uri_prefixes[i].prefix) {
@@ -199,8 +225,7 @@ bool HTTPReq_REST(AcceptedConnection *conn,
                 return uri_prefixes[i].handler(conn, strReq, mapHeaders, fRun);
             }
         }
-    }
-    catch (RestErr& re) {
+    } catch (RestErr& re) {
         conn->stream() << HTTPReply(re.status, re.message + "\r\n", false, false, "text/plain") << std::flush;
         return false;
     }