cosmium/api/handlers/middleware/authentication.go

package middleware

import (
	"fmt"
	"net/url"
	"strings"

	"github.com/gin-gonic/gin"
	"github.com/pikami/cosmium/api/config"
	"github.com/pikami/cosmium/internal/authentication"
)

func Authentication() gin.HandlerFunc {
	return func(c *gin.Context) {
		requestUrl := c.Request.URL.String()
		if config.Config.DisableAuth || strings.HasPrefix(requestUrl, "/_explorer") {
			return
		}

		var resourceType string
		parts := strings.Split(requestUrl, "/")
		switch len(parts) {
		case 2, 3:
			resourceType = parts[1]
		case 4, 5:
			resourceType = parts[3]
		case 6, 7:
			resourceType = parts[5]
		}

		databaseId, _ := c.Params.Get("databaseId")
		collId, _ := c.Params.Get("collId")
		docId, _ := c.Params.Get("docId")
		var resourceId string
		if databaseId != "" {
			resourceId += "dbs/" + databaseId
		}
		if collId != "" {
			resourceId += "/colls/" + collId
		}
		if docId != "" {
			resourceId += "/docs/" + docId
		}

		authHeader := c.Request.Header.Get("authorization")
		date := c.Request.Header.Get("x-ms-date")
		expectedSignature := authentication.GenerateSignature(
			c.Request.Method, resourceType, resourceId, date, config.Config.AccountKey)

		decoded, _ := url.QueryUnescape(authHeader)
		params, _ := url.ParseQuery(decoded)
		clientSignature := strings.Replace(params.Get("sig"), " ", "+", -1)
		if clientSignature != expectedSignature {
			fmt.Printf("Got wrong signature from client.\n- Expected: %s\n- Got: %s\n", expectedSignature, clientSignature)
			c.IndentedJSON(401, gin.H{
				"code":    "Unauthorized",
				"message": "Wrong signature.",
			})
			c.Abort()
		}
	}
}