Golang DB.Query方法代碼示例

// execute retrieves the records matching a *query, which the user can read, and marshals them to attr maps.
//
// Errors:
//		- db.Query error
//		- access.CanRead error
//		- iter.Close error
func execute(db data.DB, u *models.User, q *query) ([]map[string]interface{}, error) {
	rs := make([]map[string]interface{}, 0)

	iter, err := db.Query(q.Kind).Limit(q.Limit).Batch(q.Batch).Skip(q.Skip).Select(q.Select).Order(q.Order...).Execute()
	if err != nil {
		return nil, err
	}

	m := models.ModelFor(q.Kind)
	for iter.Next(m) {
		ok, err := access.CanRead(db, u, m)

		if err != nil {
			return nil, err
		}

		if !ok {
			continue
		}

		temp := make(map[string]interface{})
		transfer.TransferAttrs(m, &temp)
		rs = append(rs, temp)
		m = models.ModelFor(q.Kind)
	}

	if err := iter.Close(); err != nil {
		return nil, err
	}

	return rs, nil
}

// RecordQueryPOST implements gaia's response to a POST request to the '/record/query/' endpoint.
//
// Assumptions: The user has been authenticated.
//
// Proceedings:
//
// Success:
//		* StatusOK
//
// Error:
//		* InternalServerError: parsing url params,
//		* BadRequest: no kind parameter, unrecognized kind
func RecordQueryPOST(ctx context.Context, w http.ResponseWriter, r *http.Request, logger services.Logger, db data.DB) {
	l := logger.WithPrefix("RecordQueryPOST: ")

	// Parse the form
	if err := r.ParseForm(); err != nil {
		l.Printf("error parsing form: %s", err)
		http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
		return
	}

	// Retrieve the kind parameter
	k := r.FormValue(kindParam)
	if k == "" {
		l.Printf("no kind parameter")
		http.Error(w, fmt.Sprintf("You must specify a %q parameter", kindParam), http.StatusBadRequest)
		return
	}
	kind := data.Kind(k)

	// Verify the kind is recognized
	if !models.Kinds[kind] {
		l.Printf("unrecognized kind %q", kind)
		http.Error(w, fmt.Sprintf("The kind %q is not recognized", kind), http.StatusBadRequest)
		return
	}

	// Retrieve the limit, batch and skip parameters
	lim := r.FormValue(limitParam)
	bat := r.FormValue(batchParam)
	ski := r.FormValue(skipParam)

	// Set up the variables to apply to the query
	var limit, batch, skip int
	if lim != "" {
		limit, _ = strconv.Atoi(lim)
	} else if bat != "" {
		batch, _ = strconv.Atoi(bat)
	} else if ski != "" {
		skip, _ = strconv.Atoi(ski)
	}

	// Read the selection attrs from the body
	var requestBody []byte
	var err error
	defer r.Body.Close()
	if requestBody, err = ioutil.ReadAll(r.Body); err != nil {
		l.Printf("error while reading request body: %s", err)
		http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
		return
	}

	// These are the selectors, unmarshal the request body into them
	attrs := make(data.AttrMap)

	// only unmarshall if there is any request body
	if len(requestBody) > 0 {
		if err = json.Unmarshal(requestBody, &attrs); err != nil {
			l.Printf("info: request body:\n%s", string(requestBody))
			l.Printf("error: while unmarshalling request body, %s", err)
			http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
			return
		}
	}

	// Retrieve the user we are acting on behalf
	u, ok := user.FromContext(ctx)
	if !ok {
		l.Print("failed to retrieve user from context")
		http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
		return
	}

	// Load our actual query
	var iter data.Iterator
	if iter, err = db.Query(kind).Select(attrs).Limit(limit).Batch(batch).Skip(skip).Order(r.Form["order"]...).Execute(); err != nil {
		l.Printf("db.Query(%q).Select(%v).Limit(%d).Batch(%d).Skip(%d) error: %s", kind, attrs, limit, batch, skip, err)
		http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
		return
	}

	fmt.Fprint(w, "[")

	first := true

	// Iterator through the results and write the response
	m := models.ModelFor(kind)
	for iter.Next(m) {
		if !first {
//.........這裏部分代碼省略.........