[NOD-350] Implement testnet faucet (#438)

* [NOD-350] Implement testnet faucet

* [NOD-350] Add JSON annotations to api server response types

* [NOD-350] Fix IP check query, update IP usage with upsert, and make IP a primary key

* [NOD-377] Remove redundant float conversion

* [NOD-377] Change not current database error message

* [NOD-377] change API route from /money_request to /request_money

* [NOD-377] Add a constant for 24 hours

* [NOD-377] Remove redundant call for getWalletUTXOSet()

* [NOD-377] Condition refactoring

* [NOD-377] Fix POST request to API server content type

* [NOD-350] Rename day -> timeBetweenRequests

* [NOD-377] Rename timeBetweenRequests -> minRequestInterval, timeBefore24Hours -> minRequestInterval

* [NOD-350] Rename file responsetypes -> response_types

* [NOD-350] Rename convertTxModelToTxResponse -> convertTxDBModelToTxResponse

* [NOD-350] Explicitly select blue_score in fetchSelectedTipBlueScore

* [NOD-350] Refactor and add comments

* [NOD-350] Make calcFee use MassPerTxByte

* [NOD-350] Convert IP column to varchar(39) to allow ipv6 addresses

* [NOD-350] Add comments to isFundedAndIsChangeOutputRequired

* [NOD-350] Remove approximateConfirmationsForCoinbaseMaturity

* [NOD-350] Fix comments

httpserverutils/middlewares.go

@@ -0,0 +1,58 @@
+package httpserverutils
+
+import (
+	"fmt"
+	"net/http"
+	"runtime/debug"
+)
+
+var nextRequestID uint64 = 1
+
+// AddRequestMetadataMiddleware is a middleware that adds some
+// metadata to the context of every request.
+func AddRequestMetadataMiddleware(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		rCtx := ToServerContext(r.Context()).SetRequestID(nextRequestID)
+		r.WithContext(rCtx)
+		nextRequestID++
+		next.ServeHTTP(w, r)
+	})
+}
+
+// LoggingMiddleware is a middleware that writes
+// logs for every request.
+func LoggingMiddleware(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		ctx := ToServerContext(r.Context())
+		ctx.Infof("Method: %s URI: %s", r.Method, r.RequestURI)
+		next.ServeHTTP(w, r)
+	})
+}
+
+// RecoveryMiddleware is a middleware that recovers
+// from panics, log it, and sends Internal Server
+// Error to the client.
+func RecoveryMiddleware(h http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		ctx := ToServerContext(r.Context())
+		defer func() {
+			recoveryErr := recover()
+			if recoveryErr != nil {
+				recoveryErrStr := fmt.Sprintf("%s", recoveryErr)
+				log.Criticalf("Fatal error: %s", recoveryErrStr)
+				log.Criticalf("Stack trace: %s", debug.Stack())
+				SendErr(ctx, w, NewInternalServerHandlerError(recoveryErrStr))
+			}
+		}()
+		h.ServeHTTP(w, r)
+	})
+}
+
+// SetJSONMiddleware is a middleware that sets the content type of
+// every request to be application/json.
+func SetJSONMiddleware(h http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json; charset=utf-8")
+		h.ServeHTTP(w, r)
+	})
+}