path: root/resources/resource_factories/create/remote.go

// Copyright 2021 The Hugo Authors. All rights reserved.
//
// 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 create

import (
	"bufio"
	"bytes"
	"fmt"
	"io"
	"io/ioutil"
	"mime"
	"net/http"
	"net/http/httputil"
	"net/url"
	"path"
	"path/filepath"
	"strings"

	"github.com/gohugoio/hugo/common/hugio"
	"github.com/gohugoio/hugo/common/maps"
	"github.com/gohugoio/hugo/common/types"
	"github.com/gohugoio/hugo/helpers"
	"github.com/gohugoio/hugo/media"
	"github.com/gohugoio/hugo/resources"
	"github.com/gohugoio/hugo/resources/resource"
	"github.com/mitchellh/mapstructure"
)

type HTTPError struct {
	error
	Data map[string]any

	StatusCode int
	Body       string
}

func responseToData(res *http.Response, readBody bool) map[string]any {
	var body []byte
	if readBody {
		body, _ = ioutil.ReadAll(res.Body)
	}

	m := map[string]any{
		"StatusCode":       res.StatusCode,
		"Status":           res.Status,
		"TransferEncoding": res.TransferEncoding,
		"ContentLength":    res.ContentLength,
		"ContentType":      res.Header.Get("Content-Type"),
	}

	if readBody {
		m["Body"] = string(body)
	}

	return m

}

func toHTTPError(err error, res *http.Response, readBody bool) *HTTPError {
	if err == nil {
		panic("err is nil")
	}
	if res == nil {
		return &HTTPError{
			error: err,
			Data:  map[string]any{},
		}
	}

	return &HTTPError{
		error: err,
		Data:  responseToData(res, readBody),
	}
}

// FromRemote expects one or n-parts of a URL to a resource
// If you provide multiple parts they will be joined together to the final URL.
func (c *Client) FromRemote(uri string, optionsm map[string]any) (resource.Resource, error) {
	rURL, err := url.Parse(uri)
	if err != nil {
		return nil, fmt.Errorf("failed to parse URL for resource %s: %w", uri, err)
	}

	method := "GET"
	if s, ok := maps.LookupEqualFold(optionsm, "method"); ok {
		method = strings.ToUpper(s.(string))
	}
	isHeadMethod := method == "HEAD"

	resourceID := calculateResourceID(uri, optionsm)

	_, httpResponse, err := c.cacheGetResource.GetOrCreate(resourceID, func() (io.ReadCloser, error) {
		options, err := decodeRemoteOptions(optionsm)
		if err != nil {
			return nil, fmt.Errorf("failed to decode options for resource %s: %w", uri, err)
		}
		if err := c.validateFromRemoteArgs(uri, options); err != nil {
			return nil, err
		}

		req, err := options.NewRequest(uri)
		if err != nil {
			return nil, fmt.Errorf("failed to create request for resource %s: %w", uri, err)
		}

		res, err := c.httpClient.Do(req)
		if err != nil {
			return nil, err
		}
		defer res.Body.Close()

		httpResponse, err := httputil.DumpResponse(res, true)
		if err != nil {
			return nil, toHTTPError(err, res, !isHeadMethod)
		}

		if res.StatusCode != http.StatusNotFound {
			if res.StatusCode < 200 || res.StatusCode > 299 {
				return nil, toHTTPError(fmt.Errorf("failed to fetch remote resource: %s", http.StatusText(res.StatusCode)), res, !isHeadMethod)

			}
		}

		return hugio.ToReadCloser(bytes.NewReader(httpResponse)), nil
	})
	if err != nil {
		return nil, err
	}
	defer httpResponse.Close()

	res, err := http.ReadResponse(bufio.NewReader(httpResponse), nil)
	if err != nil {
		return nil, err
	}
	defer res.Body.Close()

	if res.StatusCode == http.StatusNotFound {
		// Not found. This matches how looksup for local resources work.
		return nil, nil
	}

	var (
		body      []byte
		mediaType media.Type
	)
	// A response to a HEAD method should not have a body. If it has one anyway, that body must be ignored.
	// See https://developer.mozilla.org/en-US/docs/Web/HTTP/Methods/HEAD
	if !isHeadMethod && res.Body != nil {
		body, err = ioutil.ReadAll(res.Body)
		if err != nil {
			return nil, fmt.Errorf("failed to read remote resource %q: %w", uri, err)
		}
	}

	filename := path.Base(rURL.Path)
	if _, params, _ := mime.ParseMediaType(res.Header.Get("Content-Disposition")); params != nil {
		if _, ok := params["filename"]; ok {
			filename = params["filename"]
		}
	}

	contentType := res.Header.Get("Content-Type")

	if isHeadMethod {
		// We have no body to work with, so we need to use the Content-Type header.
		mediaType, _ = media.FromString(contentType)
	} else {

		var extensionHints []string

		// mime.ExtensionsByType gives a long list of extensions for text/plain,
		// just use ".txt".
		if strings.HasPrefix(contentType, "text/plain") {
			extensionHints = []string{".txt"}
		} else {
			exts, _ := mime.ExtensionsByType(contentType)
			if exts != nil {
				extensionHints = exts
			}
		}

		// Look for a file extension. If it's .txt, look for a more specific.
		if extensionHints == nil || extensionHints[0] == ".txt" {
			if ext := path.Ext(filename); ext != "" {
				extensionHints = []string{ext}
			}
		}

		// Now resolve the media type primarily using the content.
		mediaType = media.FromContent(c.rs.MediaTypes, extensionHints, body)

	}

	if mediaType.IsZero() {
		return nil, fmt.Errorf("failed to resolve media type for remote resource %q", uri)
	}

	resourceID = filename[:len(filename)