feat: add mcp server runner and tool handlers
This commit is contained in:
thibaud-leclere
parent
656d0d7f91
commit
679abbe328
4 changed files with 527 additions and 0 deletions
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@ -7,6 +7,7 @@ import (
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"io"
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"os"
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"email-mcp/internal/mcpserver"
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"email-mcp/internal/secretstore"
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"email-mcp/internal/secretstore/kwallet"
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)
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@ -88,6 +89,8 @@ func mapAppError(err error) error {
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}
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switch {
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case errors.Is(err, mcpserver.ErrCredentialsNotConfigured):
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return newUserFacingError("credentials not configured; run `email-mcp setup`", err)
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case errors.Is(err, kwallet.ErrKWalletUnavailable):
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return newUserFacingError("kwallet is not available; make sure KDE Wallet is installed and your session D-Bus is running", err)
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case errors.Is(err, kwallet.ErrKWalletDisabled):
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17
internal/cli/app_task9_test.go
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17
internal/cli/app_task9_test.go
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@ -0,0 +1,17 @@
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package cli
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import (
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"testing"
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"email-mcp/internal/mcpserver"
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)
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func TestMapAppErrorMapsMCPMissingCredentialError(t *testing.T) {
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err := mapAppError(mcpserver.ErrCredentialsNotConfigured)
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if err == nil {
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t.Fatal("expected mapped error")
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}
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if err.Error() != "credentials not configured; run `email-mcp setup`" {
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t.Fatalf("unexpected error: %v", err)
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}
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}
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257
internal/mcpserver/server.go
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257
internal/mcpserver/server.go
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@ -0,0 +1,257 @@
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package mcpserver
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import (
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"context"
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"encoding/json"
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"errors"
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"fmt"
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"io"
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"strings"
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"email-mcp/internal/imapclient"
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"email-mcp/internal/secretstore"
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"email-mcp/internal/secretstore/kwallet"
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)
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var ErrCredentialsNotConfigured = errors.New("credentials not configured; run `email-mcp setup`")
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type MailService interface {
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ListMailboxes(context.Context, secretstore.Credential) ([]imapclient.Mailbox, error)
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ListMessages(context.Context, secretstore.Credential, string, int) ([]imapclient.MessageSummary, error)
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GetMessage(context.Context, secretstore.Credential, string, uint32) (imapclient.Message, error)
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}
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type Server struct {
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store secretstore.Store
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mail MailService
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}
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type Tool struct {
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Name string `json:"name"`
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Description string `json:"description"`
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InputSchema map[string]any `json:"input_schema,omitempty"`
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}
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type Runner struct {
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server Server
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in io.Reader
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out io.Writer
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errOut io.Writer
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}
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type toolRequest struct {
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Tool string `json:"tool"`
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Arguments json.RawMessage `json:"arguments,omitempty"`
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}
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type listMessagesArguments struct {
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Mailbox string `json:"mailbox"`
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Limit int `json:"limit,omitempty"`
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}
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type getMessageArguments struct {
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Mailbox string `json:"mailbox"`
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UID uint32 `json:"uid"`
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}
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func New(store secretstore.Store, mail MailService) Server {
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return Server{
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store: store,
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mail: mail,
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}
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}
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func NewRunner(server Server, in io.Reader, out io.Writer, errOut io.Writer) Runner {
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if out == nil {
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out = io.Discard
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}
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if errOut == nil {
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errOut = io.Discard
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}
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return Runner{
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server: server,
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in: in,
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out: out,
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errOut: errOut,
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}
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}
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func (s Server) Tools() []Tool {
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return []Tool{
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{
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Name: "list_mailboxes",
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Description: "List visible IMAP mailboxes for the configured account.",
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},
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{
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Name: "list_messages",
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Description: "List recent messages from a mailbox using IMAP UIDs.",
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InputSchema: map[string]any{
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"type": "object",
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"properties": map[string]any{
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"mailbox": map[string]any{"type": "string"},
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"limit": map[string]any{"type": "integer"},
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},
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"required": []string{"mailbox"},
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},
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},
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{
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Name: "get_message",
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Description: "Fetch a single message by mailbox and IMAP UID.",
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InputSchema: map[string]any{
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"type": "object",
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"properties": map[string]any{
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"mailbox": map[string]any{"type": "string"},
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"uid": map[string]any{"type": "integer"},
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},
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"required": []string{"mailbox", "uid"},
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},
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},
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}
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}
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func (s Server) ListMailboxes(ctx context.Context) ([]imapclient.Mailbox, error) {
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cred, err := s.loadCredential(ctx)
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if err != nil {
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return nil, err
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}
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return s.listMailboxes(ctx, cred)
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}
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func (s Server) ListMessages(ctx context.Context, mailbox string, limit int) ([]imapclient.MessageSummary, error) {
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cred, err := s.loadCredential(ctx)
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if err != nil {
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return nil, err
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}
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return s.listMessages(ctx, cred, mailbox, limit)
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}
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func (s Server) GetMessage(ctx context.Context, mailbox string, uid uint32) (imapclient.Message, error) {
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cred, err := s.loadCredential(ctx)
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if err != nil {
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return imapclient.Message{}, err
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}
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return s.getMessage(ctx, cred, mailbox, uid)
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}
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func (r Runner) Run(ctx context.Context) error {
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cred, err := r.server.loadCredential(ctx)
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if err != nil {
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return err
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}
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encoder := json.NewEncoder(r.out)
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if err := encoder.Encode(map[string]any{"tools": r.server.Tools()}); err != nil {
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return err
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}
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if r.in == nil {
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return nil
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}
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decoder := json.NewDecoder(r.in)
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for {
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if err := ctx.Err(); err != nil {
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return err
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}
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var request toolRequest
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if err := decoder.Decode(&request); err != nil {
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if errors.Is(err, io.EOF) {
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return nil
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}
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return err
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}
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result, err := r.server.handleTool(ctx, cred, request.Tool, request.Arguments)
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if err != nil {
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if encodeErr := encoder.Encode(map[string]any{"error": err.Error()}); encodeErr != nil {
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return encodeErr
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}
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continue
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}
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if err := encoder.Encode(map[string]any{"result": result}); err != nil {
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return err
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}
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}
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}
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func (s Server) handleTool(ctx context.Context, cred secretstore.Credential, name string, rawArgs json.RawMessage) (any, error) {
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switch name {
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case "list_mailboxes":
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return s.listMailboxes(ctx, cred)
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case "list_messages":
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var args listMessagesArguments
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if err := decodeArguments(rawArgs, &args); err != nil {
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return nil, err
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}
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return s.listMessages(ctx, cred, args.Mailbox, args.Limit)
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case "get_message":
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var args getMessageArguments
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if err := decodeArguments(rawArgs, &args); err != nil {
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return nil, err
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}
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return s.getMessage(ctx, cred, args.Mailbox, args.UID)
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default:
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return nil, fmt.Errorf("unknown tool: %s", name)
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}
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}
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func (s Server) listMailboxes(ctx context.Context, cred secretstore.Credential) ([]imapclient.Mailbox, error) {
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if s.mail == nil {
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return nil, fmt.Errorf("mail service is not configured")
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}
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return s.mail.ListMailboxes(ctx, cred)
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}
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func (s Server) listMessages(ctx context.Context, cred secretstore.Credential, mailbox string, limit int) ([]imapclient.MessageSummary, error) {
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if s.mail == nil {
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return nil, fmt.Errorf("mail service is not configured")
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}
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mailbox = strings.TrimSpace(mailbox)
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if mailbox == "" {
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return nil, fmt.Errorf("mailbox is required")
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}
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return s.mail.ListMessages(ctx, cred, mailbox, limit)
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}
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func (s Server) getMessage(ctx context.Context, cred secretstore.Credential, mailbox string, uid uint32) (imapclient.Message, error) {
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if s.mail == nil {
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return imapclient.Message{}, fmt.Errorf("mail service is not configured")
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}
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mailbox = strings.TrimSpace(mailbox)
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if mailbox == "" {
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return imapclient.Message{}, fmt.Errorf("mailbox is required")
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}
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if uid == 0 {
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return imapclient.Message{}, fmt.Errorf("uid must be greater than zero")
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}
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return s.mail.GetMessage(ctx, cred, mailbox, uid)
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}
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func (s Server) loadCredential(ctx context.Context) (secretstore.Credential, error) {
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if s.store == nil {
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return secretstore.Credential{}, fmt.Errorf("secret store is not configured")
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}
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cred, err := s.store.Load(ctx, secretstore.DefaultAccountKey)
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if err != nil {
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if errors.Is(err, kwallet.ErrCredentialNotFound) {
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return secretstore.Credential{}, ErrCredentialsNotConfigured
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}
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return secretstore.Credential{}, err
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}
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if err := cred.Validate(); err != nil {
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return secretstore.Credential{}, fmt.Errorf("default credential is invalid: %w", err)
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}
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return cred, nil
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}
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func decodeArguments(raw json.RawMessage, dest any) error {
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if len(raw) == 0 {
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raw = []byte("{}")
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}
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if err := json.Unmarshal(raw, dest); err != nil {
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return fmt.Errorf("invalid tool arguments: %w", err)
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}
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return nil
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}
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250
internal/mcpserver/server_test.go
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250
internal/mcpserver/server_test.go
Normal file
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@ -0,0 +1,250 @@
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package mcpserver
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import (
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"bytes"
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"context"
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"encoding/json"
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"errors"
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"testing"
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"email-mcp/internal/imapclient"
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"email-mcp/internal/secretstore"
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"email-mcp/internal/secretstore/kwallet"
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)
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type storeStub struct {
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credential secretstore.Credential
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loadErr error
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loadCalls int
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loadKey string
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}
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func (s *storeStub) Save(context.Context, string, secretstore.Credential) error {
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return nil
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}
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func (s *storeStub) Load(_ context.Context, key string) (secretstore.Credential, error) {
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s.loadCalls++
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s.loadKey = key
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if s.loadErr != nil {
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return secretstore.Credential{}, s.loadErr
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}
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return s.credential, nil
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}
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type serviceStub struct {
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listMailboxes func(context.Context, secretstore.Credential) ([]imapclient.Mailbox, error)
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listMessages func(context.Context, secretstore.Credential, string, int) ([]imapclient.MessageSummary, error)
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getMessage func(context.Context, secretstore.Credential, string, uint32) (imapclient.Message, error)
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}
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func (s serviceStub) ListMailboxes(ctx context.Context, cred secretstore.Credential) ([]imapclient.Mailbox, error) {
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return s.listMailboxes(ctx, cred)
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}
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func (s serviceStub) ListMessages(ctx context.Context, cred secretstore.Credential, mailbox string, limit int) ([]imapclient.MessageSummary, error) {
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return s.listMessages(ctx, cred, mailbox, limit)
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}
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func (s serviceStub) GetMessage(ctx context.Context, cred secretstore.Credential, mailbox string, uid uint32) (imapclient.Message, error) {
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return s.getMessage(ctx, cred, mailbox, uid)
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}
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func TestServerListMailboxesLoadsCredentialAndDelegates(t *testing.T) {
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store := &storeStub{
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credential: secretstore.Credential{
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Host: "imap.example.com",
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Username: "alice",
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Password: "secret",
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},
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}
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server := New(store, serviceStub{
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listMailboxes: func(_ context.Context, cred secretstore.Credential) ([]imapclient.Mailbox, error) {
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if cred.Host != "imap.example.com" || cred.Username != "alice" || cred.Password != "secret" {
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t.Fatalf("unexpected credential: %#v", cred)
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}
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return []imapclient.Mailbox{{Name: "INBOX"}}, nil
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},
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listMessages: func(context.Context, secretstore.Credential, string, int) ([]imapclient.MessageSummary, error) {
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t.Fatal("ListMessages should not be called")
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return nil, nil
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},
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getMessage: func(context.Context, secretstore.Credential, string, uint32) (imapclient.Message, error) {
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t.Fatal("GetMessage should not be called")
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return imapclient.Message{}, nil
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},
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})
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result, err := server.ListMailboxes(context.Background())
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if err != nil {
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t.Fatalf("ListMailboxes returned error: %v", err)
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}
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if store.loadCalls != 1 {
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t.Fatalf("expected credential to be loaded once, got %d", store.loadCalls)
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}
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if store.loadKey != secretstore.DefaultAccountKey {
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t.Fatalf("expected load key %q, got %q", secretstore.DefaultAccountKey, store.loadKey)
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}
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if len(result) != 1 || result[0].Name != "INBOX" {
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t.Fatalf("unexpected result: %#v", result)
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}
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}
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func TestServerListMessagesLoadsCredentialAndDelegates(t *testing.T) {
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store := &storeStub{
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credential: secretstore.Credential{
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Host: "imap.example.com",
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Username: "alice",
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Password: "secret",
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},
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}
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server := New(store, serviceStub{
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listMailboxes: func(context.Context, secretstore.Credential) ([]imapclient.Mailbox, error) {
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t.Fatal("ListMailboxes should not be called")
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return nil, nil
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},
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listMessages: func(_ context.Context, cred secretstore.Credential, mailbox string, limit int) ([]imapclient.MessageSummary, error) {
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if cred.Host != "imap.example.com" || mailbox != "INBOX" || limit != 5 {
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t.Fatalf("unexpected call: cred=%#v mailbox=%q limit=%d", cred, mailbox, limit)
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}
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return []imapclient.MessageSummary{{UID: 42, Subject: "hello", From: "alice@example.com"}}, nil
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},
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getMessage: func(context.Context, secretstore.Credential, string, uint32) (imapclient.Message, error) {
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t.Fatal("GetMessage should not be called")
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return imapclient.Message{}, nil
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},
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})
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result, err := server.ListMessages(context.Background(), "INBOX", 5)
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if err != nil {
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t.Fatalf("ListMessages returned error: %v", err)
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}
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if len(result) != 1 || result[0].UID != 42 {
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t.Fatalf("unexpected result: %#v", result)
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}
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}
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func TestServerGetMessageUsesUIDContract(t *testing.T) {
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store := &storeStub{
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credential: secretstore.Credential{
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Host: "imap.example.com",
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Username: "alice",
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Password: "secret",
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},
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}
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server := New(store, serviceStub{
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listMailboxes: func(context.Context, secretstore.Credential) ([]imapclient.Mailbox, error) {
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t.Fatal("ListMailboxes should not be called")
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return nil, nil
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},
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listMessages: func(context.Context, secretstore.Credential, string, int) ([]imapclient.MessageSummary, error) {
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t.Fatal("ListMessages should not be called")
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return nil, nil
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},
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getMessage: func(_ context.Context, cred secretstore.Credential, mailbox string, uid uint32) (imapclient.Message, error) {
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if cred.Host != "imap.example.com" || mailbox != "INBOX" || uid != 42 {
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t.Fatalf("unexpected call: cred=%#v mailbox=%q uid=%d", cred, mailbox, uid)
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}
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return imapclient.Message{
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UID: 42,
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Mailbox: "INBOX",
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Body: "body",
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}, nil
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},
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})
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message, err := server.GetMessage(context.Background(), "INBOX", 42)
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if err != nil {
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t.Fatalf("GetMessage returned error: %v", err)
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}
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if message.UID != 42 || message.Mailbox != "INBOX" {
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t.Fatalf("unexpected message: %#v", message)
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}
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}
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func TestRunnerRunWritesToolManifestAndHandlesRequests(t *testing.T) {
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store := &storeStub{
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credential: secretstore.Credential{
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Host: "imap.example.com",
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Username: "alice",
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Password: "secret",
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},
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}
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input := bytes.NewBufferString("{\"tool\":\"list_messages\",\"arguments\":{\"mailbox\":\"INBOX\",\"limit\":5}}\n")
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output := &bytes.Buffer{}
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runner := NewRunner(New(store, serviceStub{
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listMailboxes: func(context.Context, secretstore.Credential) ([]imapclient.Mailbox, error) {
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t.Fatal("ListMailboxes should not be called")
|
||||
return nil, nil
|
||||
},
|
||||
listMessages: func(_ context.Context, cred secretstore.Credential, mailbox string, limit int) ([]imapclient.MessageSummary, error) {
|
||||
if cred.Host != "imap.example.com" || mailbox != "INBOX" || limit != 5 {
|
||||
t.Fatalf("unexpected call: cred=%#v mailbox=%q limit=%d", cred, mailbox, limit)
|
||||
}
|
||||
return []imapclient.MessageSummary{{UID: 42, Subject: "hello", From: "alice@example.com"}}, nil
|
||||
},
|
||||
getMessage: func(context.Context, secretstore.Credential, string, uint32) (imapclient.Message, error) {
|
||||
t.Fatal("GetMessage should not be called")
|
||||
return imapclient.Message{}, nil
|
||||
},
|
||||
}), input, output, &bytes.Buffer{})
|
||||
|
||||
if err := runner.Run(context.Background()); err != nil {
|
||||
t.Fatalf("Run returned error: %v", err)
|
||||
}
|
||||
if store.loadCalls != 1 {
|
||||
t.Fatalf("expected credential preload once, got %d", store.loadCalls)
|
||||
}
|
||||
|
||||
decoder := json.NewDecoder(output)
|
||||
|
||||
var manifest struct {
|
||||
Tools []struct {
|
||||
Name string `json:"name"`
|
||||
} `json:"tools"`
|
||||
}
|
||||
if err := decoder.Decode(&manifest); err != nil {
|
||||
t.Fatalf("failed to decode manifest: %v", err)
|
||||
}
|
||||
if len(manifest.Tools) != 3 {
|
||||
t.Fatalf("expected 3 tools, got %#v", manifest.Tools)
|
||||
}
|
||||
if manifest.Tools[0].Name != "list_mailboxes" || manifest.Tools[1].Name != "list_messages" || manifest.Tools[2].Name != "get_message" {
|
||||
t.Fatalf("unexpected tool manifest: %#v", manifest.Tools)
|
||||
}
|
||||
|
||||
var response struct {
|
||||
Result []imapclient.MessageSummary `json:"result"`
|
||||
}
|
||||
if err := decoder.Decode(&response); err != nil {
|
||||
t.Fatalf("failed to decode response: %v", err)
|
||||
}
|
||||
if len(response.Result) != 1 || response.Result[0].UID != 42 {
|
||||
t.Fatalf("unexpected response: %#v", response.Result)
|
||||
}
|
||||
}
|
||||
|
||||
func TestRunnerRunReturnsFriendlyMissingCredentialError(t *testing.T) {
|
||||
store := &storeStub{
|
||||
loadErr: kwallet.ErrCredentialNotFound,
|
||||
}
|
||||
runner := NewRunner(New(store, serviceStub{
|
||||
listMailboxes: func(context.Context, secretstore.Credential) ([]imapclient.Mailbox, error) {
|
||||
t.Fatal("ListMailboxes should not be called")
|
||||
return nil, nil
|
||||
},
|
||||
listMessages: func(context.Context, secretstore.Credential, string, int) ([]imapclient.MessageSummary, error) {
|
||||
t.Fatal("ListMessages should not be called")
|
||||
return nil, nil
|
||||
},
|
||||
getMessage: func(context.Context, secretstore.Credential, string, uint32) (imapclient.Message, error) {
|
||||
t.Fatal("GetMessage should not be called")
|
||||
return imapclient.Message{}, nil
|
||||
},
|
||||
}), bytes.NewBuffer(nil), &bytes.Buffer{}, &bytes.Buffer{})
|
||||
|
||||
err := runner.Run(context.Background())
|
||||
if !errors.Is(err, ErrCredentialsNotConfigured) {
|
||||
t.Fatalf("expected missing credential error, got %v", err)
|
||||
}
|
||||
}
|
||||
Loading…
Reference in a new issue