feat(actions): add artifact listing and download (#210)

Adds the ability to list and download Gitea Actions artifacts. Extends the existing `actions_run_read` tool with four new methods rather than adding a separate tool, keeping artifacts alongside the runs/jobs/logs they belong to.

### New methods (`actions_run_read`)

| Method               | Description                                | Key params                                             |
| -------------------- | ------------------------------------------ | ------------------------------------------------------ |
| `list_artifacts`     | List all artifacts in a repository         | `owner`, `repo`, optional `artifact_name` filter       |
| `list_run_artifacts` | List artifacts for one workflow run        | `owner`, `repo`, `run_id`                              |
| `get_artifact`       | Get metadata for a single artifact         | `owner`, `repo`, `artifact_id`                         |
| `download_artifact`  | Download an artifact's zip archive to disk | `owner`, `repo`, `artifact_id`, optional `output_path` |Reviewed-on: https://gitea.com/gitea/gitea-mcp/pulls/210
Reviewed-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: bircni <bircni@icloud.com>

operation/actions/artifacts.go

@@ -0,0 +1,195 @@
+package actions
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"net/http"
+	"net/url"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+
+	"gitea.com/gitea/gitea-mcp/pkg/gitea"
+	"gitea.com/gitea/gitea-mcp/pkg/params"
+	"gitea.com/gitea/gitea-mcp/pkg/to"
+
+	"github.com/mark3labs/mcp-go/mcp"
+)
+
+// Artifact endpoints require Gitea 1.25+. Older servers answer 404/405, which is
+// surfaced as a clear "not supported" message rather than a raw HTTP error.
+func artifactNotSupportedErr(err error) error {
+	var httpErr *gitea.HTTPError
+	if errors.As(err, &httpErr) && (httpErr.StatusCode == http.StatusNotFound || httpErr.StatusCode == http.StatusMethodNotAllowed) {
+		return fmt.Errorf("actions artifacts not supported on this Gitea version (endpoint returned %d, requires Gitea 1.25+). Check https://docs.gitea.com/api/1.25/ for available Actions endpoints", httpErr.StatusCode)
+	}
+	return err
+}
+
+func listRepoActionArtifactsFn(ctx context.Context, req mcp.CallToolRequest) (*mcp.CallToolResult, error) {
+	owner, err := params.GetString(req.GetArguments(), "owner")
+	if err != nil {
+		return to.ErrorResult(err)
+	}
+	repo, err := params.GetString(req.GetArguments(), "repo")
+	if err != nil {
+		return to.ErrorResult(err)
+	}
+	page, pageSize := params.GetPagination(req.GetArguments(), 30)
+
+	query := url.Values{}
+	query.Set("page", strconv.Itoa(page))
+	query.Set("limit", strconv.Itoa(pageSize))
+	if name := params.GetOptionalString(req.GetArguments(), "artifact_name", ""); name != "" {
+		query.Set("name", name)
+	}
+
+	var result any
+	err = doJSONWithFallback(ctx, "GET",
+		[]string{
+			fmt.Sprintf("repos/%s/%s/actions/artifacts", url.PathEscape(owner), url.PathEscape(repo)),
+		},
+		query, nil, &result,
+	)
+	if err != nil {
+		return to.ErrorResult(fmt.Errorf("list action artifacts err: %v", artifactNotSupportedErr(err)))
+	}
+	return to.TextResult(slimActionArtifacts(result))
+}
+
+func listRepoActionRunArtifactsFn(ctx context.Context, req mcp.CallToolRequest) (*mcp.CallToolResult, error) {
+	owner, err := params.GetString(req.GetArguments(), "owner")
+	if err != nil {
+		return to.ErrorResult(err)
+	}
+	repo, err := params.GetString(req.GetArguments(), "repo")
+	if err != nil {
+		return to.ErrorResult(err)
+	}
+	runID, err := params.GetIndex(req.GetArguments(), "run_id")
+	if err != nil || runID <= 0 {
+		return to.ErrorResult(errors.New("run_id is required"))
+	}
+	page, pageSize := params.GetPagination(req.GetArguments(), 30)
+
+	query := url.Values{}
+	query.Set("page", strconv.Itoa(page))
+	query.Set("limit", strconv.Itoa(pageSize))
+	if name := params.GetOptionalString(req.GetArguments(), "artifact_name", ""); name != "" {
+		query.Set("name", name)
+	}
+
+	var result any
+	err = doJSONWithFallback(ctx, "GET",
+		[]string{
+			fmt.Sprintf("repos/%s/%s/actions/runs/%d/artifacts", url.PathEscape(owner), url.PathEscape(repo), runID),
+		},
+		query, nil, &result,
+	)
+	if err != nil {
+		return to.ErrorResult(fmt.Errorf("list action run artifacts err: %v", artifactNotSupportedErr(err)))
+	}
+	return to.TextResult(slimActionArtifacts(result))
+}
+
+func getRepoActionArtifactFn(ctx context.Context, req mcp.CallToolRequest) (*mcp.CallToolResult, error) {
+	owner, err := params.GetString(req.GetArguments(), "owner")
+	if err != nil {
+		return to.ErrorResult(err)
+	}
+	repo, err := params.GetString(req.GetArguments(), "repo")
+	if err != nil {
+		return to.ErrorResult(err)
+	}
+	artifactID, err := params.GetIndex(req.GetArguments(), "artifact_id")
+	if err != nil || artifactID <= 0 {
+		return to.ErrorResult(errors.New("artifact_id is required"))
+	}
+
+	var result any
+	err = doJSONWithFallback(ctx, "GET",
+		[]string{
+			fmt.Sprintf("repos/%s/%s/actions/artifacts/%d", url.PathEscape(owner), url.PathEscape(repo), artifactID),
+		},
+		nil, nil, &result,
+	)
+	if err != nil {
+		return to.ErrorResult(fmt.Errorf("get action artifact err: %v", artifactNotSupportedErr(err)))
+	}
+	return to.TextResult(slimActionArtifact(result))
+}
+
+func downloadRepoActionArtifactFn(ctx context.Context, req mcp.CallToolRequest) (*mcp.CallToolResult, error) {
+	owner, err := params.GetString(req.GetArguments(), "owner")
+	if err != nil {
+		return to.ErrorResult(err)
+	}
+	repo, err := params.GetString(req.GetArguments(), "repo")
+	if err != nil {
+		return to.ErrorResult(err)
+	}
+	artifactID, err := params.GetIndex(req.GetArguments(), "artifact_id")
+	if err != nil || artifactID <= 0 {
+		return to.ErrorResult(errors.New("artifact_id is required"))
+	}
+	outputPath, _ := req.GetArguments()["output_path"].(string)
+
+	// Best-effort metadata lookup: gives a friendly filename and lets us fail
+	// early with a clear message when the artifact has expired.
+	var meta map[string]any
+	_ = doJSONWithFallback(ctx, "GET",
+		[]string{fmt.Sprintf("repos/%s/%s/actions/artifacts/%d", url.PathEscape(owner), url.PathEscape(repo), artifactID)},
+		nil, nil, &meta,
+	)
+	if expired, ok := meta["expired"].(bool); ok && expired {
+		return to.ErrorResult(fmt.Errorf("artifact %d has expired and is no longer downloadable", artifactID))
+	}
+
+	// The zip endpoint answers with a 302 redirect to signed blob storage;
+	// DoBytes follows GET redirects and returns the archive bytes.
+	raw, _, err := gitea.DoBytes(ctx, "GET",
+		fmt.Sprintf("repos/%s/%s/actions/artifacts/%d/zip", url.PathEscape(owner), url.PathEscape(repo), artifactID),
+		nil, nil, "application/zip",
+	)
+	if err != nil {
+		return to.ErrorResult(fmt.Errorf("download action artifact err: %v", artifactNotSupportedErr(err)))
+	}
+
+	if outputPath == "" {
+		home, _ := os.UserHomeDir()
+		if home == "" {
+			home = os.TempDir()
+		}
+		outputPath = filepath.Join(home, ".gitea-mcp", "artifacts", "actions-artifacts", owner, repo, artifactFilename(meta, artifactID))
+	}
+
+	if err := os.MkdirAll(filepath.Dir(outputPath), 0o700); err != nil {
+		return to.ErrorResult(fmt.Errorf("create output dir err: %v", err))
+	}
+	if err := os.WriteFile(outputPath, raw, 0o600); err != nil {
+		return to.ErrorResult(fmt.Errorf("write artifact file err: %v", err))
+	}
+
+	res := map[string]any{
+		"artifact_id": artifactID,
+		"path":        outputPath,
+		"bytes":       len(raw),
+	}
+	if name, ok := meta["name"].(string); ok && name != "" {
+		res["name"] = name
+	}
+	return to.TextResult(res)
+}
+
+// artifactFilename derives a safe "<name>.zip" filename from artifact metadata,
+// falling back to the artifact ID when the name is missing or path-unsafe.
+func artifactFilename(meta map[string]any, artifactID int64) string {
+	name, _ := meta["name"].(string)
+	name = strings.TrimSpace(name)
+	if name != "" && !strings.ContainsAny(name, `/\`) && name != "." && name != ".." {
+		return name + ".zip"
+	}
+	return fmt.Sprintf("%d.zip", artifactID)
+}