From 24285e8d32ffec2c9ab8aa28137a6f38349fa9d4 Mon Sep 17 00:00:00 2001
From: Denis Arh <denis.arh@gmail.com>
Date: Mon, 26 Oct 2020 07:15:59 +0100
Subject: [PATCH] Support custom parsers for REST params

---
 pkg/codegen/assets/rest_request.go.tpl | 40 ++++++++++++++++----------
 pkg/codegen/rest.go                    | 10 +++++++
 2 files changed, 35 insertions(+), 15 deletions(-)

diff --git a/pkg/codegen/assets/rest_request.go.tpl b/pkg/codegen/assets/rest_request.go.tpl
index 5640088d0..ca80621cc 100644
--- a/pkg/codegen/assets/rest_request.go.tpl
+++ b/pkg/codegen/assets/rest_request.go.tpl
@@ -87,15 +87,7 @@ func (r *{{ export $.Endpoint.Entrypoint $a.Name }}) Fill(req *http.Request) (er
         // GET params
 	    tmp := req.URL.Query()
 	{{ range $p := $a.Params.Get }}
-        {{- if not $p.IsSlice }}
-        if val, ok := tmp["{{ $p.Name }}"]; ok && len(val) > 0  {
-            r.{{ export $p.Name }}, err = {{ $p.Parser "val[0]" }}
-            if err != nil {
-                return err
-            }
-        }
-        {{- end }}
-        {{- if $p.IsSlice }}
+        {{- if or $p.IsSlice $p.HasExplicitParser }}
         if val, ok := tmp["{{ $p.Name }}[]"]; ok   {
             r.{{ export $p.Name }}, err = {{ $p.Parser "val" }}
             if err != nil {
@@ -107,6 +99,13 @@ func (r *{{ export $.Endpoint.Entrypoint $a.Name }}) Fill(req *http.Request) (er
                 return err
             }
         }
+        {{- else }}
+        if val, ok := tmp["{{ $p.Name }}"]; ok && len(val) > 0  {
+            r.{{ export $p.Name }}, err = {{ $p.Parser "val[0]" }}
+            if err != nil {
+                return err
+            }
+        }
         {{- end }}
     {{- end }}
 	}
@@ -125,21 +124,32 @@ func (r *{{ export $.Endpoint.Entrypoint $a.Name }}) Fill(req *http.Request) (er
                 return fmt.Errorf("error processing uploaded file: %w", err)
             }
             {{ else }}
-                {{- if not $p.IsSlice }}
-                if val, ok := req.Form["{{ $p.Name }}"]; ok && len(val) > 0  {
-                    r.{{ export $p.Name }}, err = {{ $p.Parser "val[0]" }}
+                {{- if or $p.HasExplicitParser }}
+                if val, ok := req.Form["{{ $p.Name }}[]"]; ok {
+                    r.{{ export $p.Name }}, err = {{ $p.Parser "val" }}
                     if err != nil {
                         return err
                     }
-                }
-                {{- end }}
-                {{- if $p.IsSlice }}
+                } else if val, ok := req.Form["{{ $p.Name }}"]; ok   {
+					r.{{ export $p.Name }}, err = {{ $p.Parser "val" }}
+					if err != nil {
+						return err
+					}
+				}
+                {{- else if or $p.IsSlice }}
                 //if val, ok := req.Form["{{ $p.Name }}[]"]; ok && len(val) > 0  {
                 //    r.{{ export $p.Name }}, err = {{ $p.Parser "val" }}
                 //    if err != nil {
                 //        return err
                 //    }
                 //}
+                {{- else }}
+                if val, ok := req.Form["{{ $p.Name }}"]; ok && len(val) > 0  {
+                    r.{{ export $p.Name }}, err = {{ $p.Parser "val[0]" }}
+                    if err != nil {
+                        return err
+                    }
+                }
                 {{- end }}
             {{- end }}
 
diff --git a/pkg/codegen/rest.go b/pkg/codegen/rest.go
index 5750975e1..14da5041a 100644
--- a/pkg/codegen/rest.go
+++ b/pkg/codegen/rest.go
@@ -55,6 +55,8 @@ type (
 		Required bool   `yaml:"required"`
 		Title    string `yaml:"title"`
 		Origin   string
+
+		DefinedParser string `yaml:"parser"`
 	}
 )
 
@@ -191,7 +193,15 @@ func (d *restEndpointParamDef) FieldTag() string {
 	return ""
 }
 
+func (d *restEndpointParamDef) HasExplicitParser() bool {
+	return d.DefinedParser != ""
+}
+
 func (d *restEndpointParamDef) Parser(arg string) string {
+	if d.HasExplicitParser() {
+		return fmt.Sprintf("%s(%s)", d.DefinedParser, arg)
+	}
+
 	switch d.Type {
 	case "[]uint64":
 		return fmt.Sprintf("payload.ParseUint64s(%s), nil", arg)