Allow custom headers on Config, improve docs and GetRestyClientWithCustomHeaders logic

cli/packages/util/common.go

@@ -5,6 +5,7 @@ import (
 	"net/http"
 	"os"
 	"strings"
+	"unicode"
 
 	"github.com/Infisical/infisical-merge/packages/config"
 	"github.com/go-resty/resty/v2"
@@ -35,18 +36,67 @@ func GetRestyClientWithCustomHeaders() (*resty.Client, error) {
 	customHeaders := os.Getenv("INFISICAL_CUSTOM_HEADERS")
 	if customHeaders != "" {
 		headers := map[string]string{}
-		pairs := strings.Split(customHeaders, " ")
-		for _, pair := range pairs {
-			kv := strings.SplitN(pair, "=", 2)
-			if len(kv) != 2 {
+
+		pos := 0
+		for pos < len(customHeaders) {
+			for pos < len(customHeaders) && unicode.IsSpace(rune(customHeaders[pos])) {
+				pos++
+			}
+
+			if pos >= len(customHeaders) {
+				break
+			}
+
+			keyStart := pos
+			for pos < len(customHeaders) && customHeaders[pos] != '=' && !unicode.IsSpace(rune(customHeaders[pos])) {
+				pos++
+			}
+
+			if pos >= len(customHeaders) || customHeaders[pos] != '=' {
 				return nil, fmt.Errorf("invalid custom header format. Expected \"headerKey1=value1 headerKey2=value2 ....\" but got %v", customHeaders)
 			}
-			key := strings.TrimSpace(kv[0])
-			value := strings.TrimSpace(kv[1])
-			if !strings.EqualFold(key, "User-Agent") && !strings.EqualFold(key, "Accept") {
+
+			key := customHeaders[keyStart:pos]
+			pos++
+
+			for pos < len(customHeaders) && unicode.IsSpace(rune(customHeaders[pos])) {
+				pos++
+			}
+
+			var value string
+
+			if pos < len(customHeaders) {
+				if customHeaders[pos] == '"' || customHeaders[pos] == '\'' {
+					quoteChar := customHeaders[pos]
+					pos++
+					valueStart := pos
+
+					for pos < len(customHeaders) &&
+						(customHeaders[pos] != quoteChar ||
+							(pos > 0 && customHeaders[pos-1] == '\\')) {
+						pos++
+					}
+
+					if pos < len(customHeaders) {
+						value = customHeaders[valueStart:pos]
+						pos++
+					} else {
+						value = customHeaders[valueStart:]
+					}
+				} else {
+					valueStart := pos
+					for pos < len(customHeaders) && !unicode.IsSpace(rune(customHeaders[pos])) {
+						pos++
+					}
+					value = customHeaders[valueStart:pos]
+				}
+			}
+
+			if key != "" && !strings.EqualFold(key, "User-Agent") && !strings.EqualFold(key, "Accept") {
 				headers[key] = value
 			}
 		}
+
 		httpClient.SetHeaders(headers)
 	}
 	return httpClient, nil