Merge branch 'add_oauth1_signature_generator' into 'main'

Add OAuth1.0 header generation

See merge request !38

auth/oauth.go

+package oauth
+
+import (
+	"github.com/aws/aws-sdk-go/aws"
+	"gitlab.bob.co.za/bob-public-utils/bobgroup-go-utils/encryption"
+	"math/rand"
+	"net/url"
+	"strconv"
+	"strings"
+	"time"
+)
+
+type Oauth1 struct {
+	ConsumerKey    string
+	ConsumerSecret string
+	AccessToken    string
+	AccessSecret   string
+}
+
+func (auth Oauth1) GenerateAuthorizationHeader(method, requestUrl string) (AuthorizationValue *string, err error) {
+
+	// Take the URL and get all its parts
+	urlParts, err := url.Parse(requestUrl)
+	if err != nil {
+		return nil, err
+	}
+
+	// Get the query parameters from the URL and make it easier to work with
+	rawParams, err := url.ParseQuery(urlParts.RawQuery)
+	if err != nil {
+		return nil, err
+	}
+	params := make(map[string]string)
+	for key, _ := range rawParams {
+		params[key] = rawParams.Get(key)
+	}
+
+	urlValues := url.Values{}
+	urlValues.Add("oauth_nonce", generateNonce())
+	urlValues.Add("oauth_consumer_key", auth.ConsumerKey)
+	urlValues.Add("oauth_signature_method", "HMAC-SHA256")
+	urlValues.Add("oauth_timestamp", strconv.Itoa(int(time.Now().Unix())))
+	urlValues.Add("oauth_token", auth.AccessToken)
+	urlValues.Add("oauth_version", "1.0")
+
+	for k, v := range params {
+		urlValues.Add(k, v)
+	}
+
+	// If there are any '+' encoded spaces replace them with the proper urlencoded version of a space
+	parameterString := strings.Replace(urlValues.Encode(), "+", "%20", -1)
+
+	// Build the signature
+	signatureBase := strings.ToUpper(method) + "&" + url.QueryEscape(strings.Split(requestUrl, "?")[0]) + "&" + url.QueryEscape(parameterString)
+	signingKey := url.QueryEscape(auth.ConsumerSecret) + "&" + url.QueryEscape(auth.AccessSecret)
+	signature := encryption.Hash(signatureBase, signingKey)
+
+	// Populate all the authorisation parameters
+	authParams := map[string]string{
+		"oauth_consumer_key":     url.QueryEscape(urlValues.Get("oauth_consumer_key")),
+		"oauth_nonce":            url.QueryEscape(urlValues.Get("oauth_nonce")),
+		"oauth_signature":        url.QueryEscape(signature),
+		"oauth_signature_method": url.QueryEscape(urlValues.Get("oauth_signature_method")),
+		"oauth_timestamp":        url.QueryEscape(urlValues.Get("oauth_timestamp")),
+		"oauth_token":            url.QueryEscape(urlValues.Get("oauth_token")),
+		"oauth_version":          url.QueryEscape(urlValues.Get("oauth_version")),
+	}
+
+	// Convert all the parameters into a comma delimited string with values defined as ""
+	var AuthorizationString string
+	for k, v := range authParams {
+		AuthorizationString += k + "=\"" + v + "\","
+	}
+
+	return aws.String("OAuth " + strings.TrimSuffix(AuthorizationString, ",")), nil
+}
+
+func generateNonce() string {
+	const allowed = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
+	b := make([]byte, 48)
+	for i := range b {
+		b[i] = allowed[rand.Intn(len(allowed))]
+	}
+	return string(b)
+}