Include support to headers in URL Resource (#282)

* feat: include support to headers in url resource

* fix lint

Author: ralphg6

docs/cn/Tutorial_cn.md

@@ -232,6 +232,18 @@ if err != nil {
 }
 ```
 
+#### 帶標題
+
+```go
+headers := make(http.Header)
+headers.Set("Authorization", "Basic YWxhZGRpbjpvcGVuc2VzYW1l")
+urlRes := pkg.NewURLResourceWithHeaders("http://host.com/path/to/rule.grl", headers)
+err := ruleBuilder.BuildRuleFromResource("TutorialRules", "0.0.1", urlRes)
+if err != nil {
+    panic(err)
+}
+```
+
 ### 从Git获取
 
 ```go

docs/de/Tutorial_de.md

@@ -276,6 +276,18 @@ if err != nil {
 }
 ```
 
+#### With Headers
+
+```go
+headers := make(http.Header)
+headers.Set("Authorization", "Basic YWxhZGRpbjpvcGVuc2VzYW1l")
+urlRes := pkg.NewURLResourceWithHeaders("http://host.com/path/to/rule.grl", headers)
+err := ruleBuilder.BuildRuleFromResource("TutorialRules", "0.0.1", urlRes)
+if err != nil {
+    panic(err)
+}
+```
+
 ### From GIT
 
 ```go

docs/en/Tutorial_en.md

@@ -263,6 +263,18 @@ if err != nil {
 }
 ```
 
+#### With Headers
+
+```go
+headers := make(http.Header)
+headers.Set("Authorization", "Basic YWxhZGRpbjpvcGVuc2VzYW1l")
+urlRes := pkg.NewURLResourceWithHeaders("http://host.com/path/to/rule.grl", headers)
+err := ruleBuilder.BuildRuleFromResource("TutorialRules", "0.0.1", urlRes)
+if err != nil {
+    panic(err)
+}
+```
+
 ### From GIT
 
 ```go

docs/id/Tutorial_id.md

@@ -298,6 +298,18 @@ if err != nil {
 }
 ```
 
+#### With Headers
+
+```go
+headers := make(http.Header)
+headers.Set("Authorization", "Basic YWxhZGRpbjpvcGVuc2VzYW1l")
+urlRes := pkg.NewURLResourceWithHeaders("http://host.com/path/to/rule.grl", headers)
+err := ruleBuilder.BuildRuleFromResource("TutorialRules", "0.0.1", urlRes)
+if err != nil {
+    panic(err)
+}
+```
+
 ### From GIT
 
 ```go

examples/EvaluateMissingDataContext_test.go

@@ -2,15 +2,16 @@ package examples
 
 import (
 	"fmt"
+	"testing"
+
 	"github.com/hyperjumptech/grule-rule-engine/ast"
 	"github.com/hyperjumptech/grule-rule-engine/builder"
 	"github.com/hyperjumptech/grule-rule-engine/engine"
 	"github.com/hyperjumptech/grule-rule-engine/pkg"
-	"testing"
 )
 
 const (
-	input_rule = `
+	inputRule = `
 	rule TestRule "" {
 		when
 			R.Result == 'NoResult' &&
@@ -22,7 +23,6 @@ const (
 	`
 )
 
-
 func TestDataContextMissingFact(t *testing.T) {
 
 	oresult := &ObjectResult{
@@ -32,7 +32,7 @@ func TestDataContextMissingFact(t *testing.T) {
 	// build rules
 	lib := ast.NewKnowledgeLibrary()
 	rb := builder.NewRuleBuilder(lib)
-	err := rb.BuildRuleFromResource("Test", "0.0.1", pkg.NewBytesResource([]byte(input_rule)))
+	err := rb.BuildRuleFromResource("Test", "0.0.1", pkg.NewBytesResource([]byte(inputRule)))
 
 	// 	add JSON fact
 	json := []byte(`{"blabla":"bla","name":{"first":"john","last":"doe"}}`)
@@ -48,4 +48,4 @@ func TestDataContextMissingFact(t *testing.T) {
 	// results in panic
 	engine.NewGruleEngine().Execute(dcx, kb)
 
-}
+}

pkg/resource.go

@@ -16,12 +16,13 @@ package pkg
 
 import (
 	"fmt"
-	"github.com/hyperjumptech/grule-rule-engine/logger"
 	"io"
 	"io/ioutil"
 	"net/http"
 	"path/filepath"
 
+	"github.com/hyperjumptech/grule-rule-engine/logger"
+
 	"github.com/bmatcuk/doublestar"
 	"gopkg.in/src-d/go-billy.v4"
 )
@@ -201,14 +202,24 @@ func (res *BytesResource) String() string {
 // NewURLResource will create a new Resource using a resource as located in the url
 func NewURLResource(url string) Resource {
 	return &URLResource{
-		URL: url,
+		URL:    url,
+		Header: make(http.Header),
+	}
+}
+
+// NewURLResourceWithHeaders will create a new Resource using a resource as located in the url with headers
+func NewURLResourceWithHeaders(url string, Header http.Header) Resource {
+	return &URLResource{
+		URL:    url,
+		Header: Header,
 	}
 }
 
 // URLResource is a struct that will hold the byte array data and URL source
 type URLResource struct {
-	URL   string
-	Bytes []byte
+	URL    string
+	Header http.Header
+	Bytes  []byte
 }
 
 // String will state the resource url.
@@ -224,7 +235,15 @@ func (res *URLResource) Load() ([]byte, error) {
 	if res.Bytes != nil {
 		return res.Bytes, nil
 	}
-	resp, err := http.Get(res.URL)
+	client := &http.Client{}
+	req, err := http.NewRequest("GET", res.URL, nil)
+	if len(res.Header) > 0 {
+		req.Header = res.Header
+	}
+	if err != nil {
+		return nil, err
+	}
+	resp, err := client.Do(req)
 	if err != nil {
 		return nil, err
 	}