acquire personal access token with longer expiry

Author: hickford

README.md

@@ -8,7 +8,6 @@ git-credential-azure is a Git credential helper that authenticates to [Azure Rep
 This is alpha-release software early in development:
 
 * Untested with work and school Microsoft accounts.
-* Tokens expire after 1 hour so you have to reauthenticate regularly.
 
 A mature alternative is [Git Credential Manager](https://github.com/GitCredentialManager/git-credential-manager).
 
@@ -34,6 +33,7 @@ This assumes you already have a storage helper configured such as cache or wincr
 
 ```sh
 git config --global --add credential.helper azure
+git config --global credential.https://dev.azure.com.useHttpPath true
 ```
 
 ### Unconfiguration

main.go

@@ -1,14 +1,19 @@
 package main
 
 import (
+	"bytes"
 	"context"
+	"encoding/json"
+	"errors"
 	"flag"
 	"fmt"
 	"io"
 	"log"
+	"net/http"
 	"os"
 	"runtime/debug"
 	"strings"
+	"time"
 
 	"github.com/AzureAD/microsoft-authentication-library-for-go/apps/public"
 )
@@ -82,18 +87,35 @@ func main() {
 		if verbose {
 			fmt.Fprintln(os.Stderr, "result:", result)
 		}
+		organization := strings.SplitN(pairs["path"], "/", 2)[0]
+		var pt PatToken
+		if organization != "" {
+			pt, err = getPAT(organization, result.AccessToken)
+			if err != nil {
+				fmt.Fprintln(os.Stderr, "error acquiring Personal Access Token", err)
+			}
+		}
 		var username string
 		if pairs["username"] == "" {
+			// TODO: check correctness
 			username = "oauth2"
 		}
-		output := map[string]string{
-			"password": result.AccessToken,
-		}
+		output := map[string]string{}
 		if username != "" {
 			output["username"] = username
 		}
-		if !result.ExpiresOn.IsZero() {
-			output["password_expiry_utc"] = fmt.Sprintf("%d", result.ExpiresOn.UTC().Unix())
+		var password string
+		var expiry time.Time
+		if pt.Token != "" {
+			password = pt.Token
+			expiry = pt.ValidTo
+		} else {
+			password = result.AccessToken
+			expiry = result.ExpiresOn
+		}
+		output["password"] = password
+		if !expiry.IsZero() {
+			output["password_expiry_utc"] = fmt.Sprintf("%d", expiry.UTC().Unix())
 		}
 		if verbose {
 			fmt.Fprintln(os.Stderr, "output:", output)
@@ -106,11 +128,65 @@ func main() {
 
 func authenticate() (public.AuthResult, error) {
 	client, err := public.New(
+		// https://github.com/git-ecosystem/git-credential-manager/blob/8c430c9484c90433ab30c25df7fc1005fe2f4ba4/src/shared/Microsoft.AzureRepos/AzureDevOpsConstants.cs#L15
+		// magic https://developercommunity.visualstudio.com/t/non-interactive-aad-auth-works-for-visual-studio-a/387853
 		"872cd9fa-d31f-45e0-9eab-6e460a02d1f1",
 		public.WithAuthority("https://login.microsoftonline.com/organizations"))
 	if err != nil {
 		return public.AuthResult{}, err
 	}
+	// https://learn.microsoft.com/en-us/azure/devops/organizations/accounts/manage-personal-access-tokens-via-api?view=azure-devops
 	scopes := []string{"499b84ac-1321-427f-aa17-267ca6975798/.default"}
 	return client.AcquireTokenInteractive(context.Background(), scopes)
 }
+
+func getPAT(organization, accessToken string) (PatToken, error) {
+	// https://learn.microsoft.com/en-us/rest/api/azure/devops/tokens/pats/create?view=azure-devops-rest-7.1&tabs=HTTP
+	// sadly https://github.com/microsoft/azure-devops-go-api doesn't have this function
+	url := fmt.Sprintf("https://vssps.dev.azure.com/%s/_apis/tokens/pats?api-version=7.1-preview.1", organization)
+	j := map[string]any{
+		"scopes": "vso.code_write vso.packaging",
+	}
+	body, err := json.Marshal(j)
+	if err != nil {
+		return PatToken{}, err
+	}
+	req, err := http.NewRequest("POST", url, bytes.NewReader(body))
+	if err != nil {
+		return PatToken{}, err
+	}
+	req.Header.Set("Content-Type", "application/json")
+	req.Header.Add("Authorization", fmt.Sprintf("Bearer %s", accessToken))
+	response, err := http.DefaultClient.Do(req)
+	if err != nil {
+		return PatToken{}, err
+	}
+	body, err = io.ReadAll(response.Body)
+	if err != nil {
+		return PatToken{}, err
+	}
+	if verbose {
+		fmt.Fprintln(os.Stderr, string(body))
+	}
+	ptr := PatTokenResult{}
+	err = json.Unmarshal(body, &ptr)
+	if err != nil {
+		return PatToken{}, err
+	}
+	if ptr.PatTokenError != "" && ptr.PatTokenError != "none" {
+		return PatToken{}, errors.New(ptr.PatTokenError)
+	}
+	return ptr.PatToken, nil
+}
+
+// https://learn.microsoft.com/en-us/rest/api/azure/devops/tokens/pats/create?view=azure-devops-rest-7.1&tabs=HTTP#pattokenresult
+type PatTokenResult struct {
+	PatToken      PatToken `json:"patToken"`
+	PatTokenError string   `json:"patTokenError"`
+}
+
+// https://learn.microsoft.com/en-us/rest/api/azure/devops/tokens/pats/create?view=azure-devops-rest-7.1&tabs=HTTP#pattoken
+type PatToken struct {
+	Token   string    `json:"token"`
+	ValidTo time.Time `json:"validTo"`
+}