graphql-engine/cli/plugins/download/fetch.go

// Copyright 2019 The Kubernetes Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package download

import (
	"fmt"
	"io"
	"net/http"
	"os"

	"github.com/hasura/graphql-engine/cli/v2/internal/errors"
)

// Fetcher is used to get files from a URI.
type Fetcher interface {
	// Get gets the file and returns an stream to read the file.
	Get(uri string) (io.ReadCloser, error)
}

var _ Fetcher = HTTPFetcher{}

// HTTPFetcher is used to get a file from a http:// or https:// schema path.
type HTTPFetcher struct{}

// Get gets the file and returns an stream to read the file.
func (HTTPFetcher) Get(uri string) (io.ReadCloser, error) {
	var op errors.Op = "download.HTTPFetcher.Get"
	resp, err := http.Get(uri)
	if err != nil {
		return nil, errors.E(op, errors.KindNetwork, fmt.Errorf("failed to download %q: %w", uri, err))
	}
	return resp.Body, nil
}

var _ Fetcher = fileFetcher{}

type fileFetcher struct{ f string }

func (f fileFetcher) Get(_ string) (io.ReadCloser, error) {
	var op errors.Op = "download.fileFetcher.Get"
	file, err := os.Open(f.f)
	if err != nil {
		return file, errors.E(op, fmt.Errorf("failed to open archive file %q for reading: %w", f.f, err))
	}
	return file, nil
}

// NewFileFetcher returns a local file reader.
func NewFileFetcher(path string) Fetcher { return fileFetcher{f: path} }