element-web/src/components/views/messages/MImageBody.js

/*
Copyright 2015, 2016 OpenMarket Ltd

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.
*/

'use strict';

import React from 'react';
import PropTypes from 'prop-types';
import { MatrixClient } from 'matrix-js-sdk';

import MFileBody from './MFileBody';
import Modal from '../../../Modal';
import sdk from '../../../index';
import { decryptFile } from '../../../utils/DecryptFile';
import Promise from 'bluebird';
import { _t } from '../../../languageHandler';
import SettingsStore from "../../../settings/SettingsStore";

const THUMBNAIL_MAX_HEIGHT = 600;

export default class extends React.Component {
    displayName: 'MImageBody'

    static propTypes = {
        /* the MatrixEvent to show */
        mxEvent: PropTypes.object.isRequired,

        /* called when the image has loaded */
        onWidgetLoad: PropTypes.func.isRequired,
    }

    static contextTypes = {
        matrixClient: PropTypes.instanceOf(MatrixClient),
    }

    constructor(props) {
        super(props);

        this.onImageError = this.onImageError.bind(this);
        this.onImageLoad = this.onImageLoad.bind(this);
        this.onImageEnter = this.onImageEnter.bind(this);
        this.onImageLeave = this.onImageLeave.bind(this);
        this.onClientSync = this.onClientSync.bind(this);
        this.onClick = this.onClick.bind(this);
        this._isGif = this._isGif.bind(this);

        this.state = {
            decryptedUrl: null,
            decryptedThumbnailUrl: null,
            decryptedBlob: null,
            error: null,
            imgError: false,
        };
    }

    componentWillMount() {
        this.unmounted = false;
        this.context.matrixClient.on('sync', this.onClientSync);
    }

    // FIXME: factor this out and aplpy it to MVideoBody and MAudioBody too!
    onClientSync(syncState, prevState) {
        if (this.unmounted) return;
        // Consider the client reconnected if there is no error with syncing.
        // This means the state could be RECONNECTING, SYNCING or PREPARED.
        const reconnected = syncState !== "ERROR" && prevState !== syncState;
        if (reconnected && this.state.imgError) {
            // Load the image again
            this.setState({
                imgError: false,
            });
        }
    }

    onClick(ev) {
        if (ev.button == 0 && !ev.metaKey) {
            ev.preventDefault();
            const content = this.props.mxEvent.getContent();
            const httpUrl = this._getContentUrl();
            const ImageView = sdk.getComponent("elements.ImageView");
            const params = {
                src: httpUrl,
                name: content.body && content.body.length > 0 ? content.body : _t('Attachment'),
                mxEvent: this.props.mxEvent,
            };

            if (content.info) {
                params.width = content.info.w;
                params.height = content.info.h;
                params.fileSize = content.info.size;
            }

            Modal.createDialog(ImageView, params, "mx_Dialog_lightbox");
        }
    }

    _isGif() {
        const content = this.props.mxEvent.getContent();
        return (
          content &&
          content.info &&
          content.info.mimetype === "image/gif"
        );
    }

    onImageEnter(e) {
        if (!this._isGif() || SettingsStore.getValue("autoplayGifsAndVideos")) {
            return;
        }
        const imgElement = e.target;
        imgElement.src = this._getContentUrl();
    }

    onImageLeave(e) {
        if (!this._isGif() || SettingsStore.getValue("autoplayGifsAndVideos")) {
            return;
        }
        const imgElement = e.target;
        imgElement.src = this._getThumbUrl();
    }

    onImageError() {
        this.setState({
            imgError: true,
        });
    }

    onImageLoad() {
        this.props.onWidgetLoad();
    }

    _getContentUrl() {
        const content = this.props.mxEvent.getContent();
        if (content.file !== undefined) {
            return this.state.decryptedUrl;
        } else {
            return this.context.matrixClient.mxcUrlToHttp(content.url);
        }
    }

    _getThumbUrl() {
        const content = this.props.mxEvent.getContent();
        if (content.file !== undefined) {
            // Don't use the thumbnail for clients wishing to autoplay gifs.
            if (this.state.decryptedThumbnailUrl) {
                return this.state.decryptedThumbnailUrl;
            }
            return this.state.decryptedUrl;
        } else if (content.info &&
                   content.info.mimetype == "image/svg+xml" &&
                   content.info.thumbnail_url) {
            // special case to return client-generated thumbnails for SVGs, if any,
            // given we deliberately don't thumbnail them serverside to prevent
            // billion lol attacks and similar
            return this.context.matrixClient.mxcUrlToHttp(
                content.info.thumbnail_url, 800, 600,
            );
        } else {
            return this.context.matrixClient.mxcUrlToHttp(content.url, 800, 600);
        }
    }

    componentDidMount() {
        const content = this.props.mxEvent.getContent();
        if (content.file !== undefined && this.state.decryptedUrl === null) {
            let thumbnailPromise = Promise.resolve(null);
            if (content.info.thumbnail_file) {
                thumbnailPromise = decryptFile(
                    content.info.thumbnail_file,
                ).then(function(blob) {
                    return URL.createObjectURL(blob);
                });
            }
            let decryptedBlob;
            thumbnailPromise.then((thumbnailUrl) => {
                return decryptFile(content.file).then(function(blob) {
                    decryptedBlob = blob;
                    return URL.createObjectURL(blob);
                }).then((contentUrl) => {
                    this.setState({
                        decryptedUrl: contentUrl,
                        decryptedThumbnailUrl: thumbnailUrl,
                        decryptedBlob: decryptedBlob,
                    });
                });
            }).catch((err) => {
                console.warn("Unable to decrypt attachment: ", err);
                // Set a placeholder image when we can't decrypt the image.
                this.setState({
                    error: err,
                });
            }).done();
        }
        this._afterComponentDidMount();
    }

    // To be overridden by subclasses (e.g. MStickerBody) for further
    // initialisation after componentDidMount
    _afterComponentDidMount() {
    }

    componentWillUnmount() {
        this.unmounted = true;
        this.context.matrixClient.removeListener('sync', this.onClientSync);
        this._afterComponentWillUnmount();

        if (this.state.decryptedUrl) {
            URL.revokeObjectURL(this.state.decryptedUrl);
        }
        if (this.state.decryptedThumbnailUrl) {
            URL.revokeObjectURL(this.state.decryptedThumbnailUrl);
        }
    }

    // To be overridden by subclasses (e.g. MStickerBody) for further
    // cleanup after componentWillUnmount
    _afterComponentWillUnmount() {
    }

    _messageContent(contentUrl, thumbUrl, content) {
        const maxHeight = Math.min(THUMBNAIL_MAX_HEIGHT, content.info.h);
        const maxWidth = content.info.w * maxHeight / content.info.h;
        const thumbnail = (
            <a href={contentUrl} onClick={this.onClick}>
                <div className="mx_MImageBody_thumbnail_container" style={{ "max-height": maxHeight + "px" }} >
                    { /* Calculate aspect ratio, using %padding will size _container correctly */ }
                    <div style={{ paddingBottom: (100 * content.info.h / content.info.w) + '%' }}></div>

                    { /* Thumbnail CSS class resizes to exactly container size with inline CSS
                         to restrict width */ }
                    <img className="mx_MImageBody_thumbnail" src={thumbUrl} ref="image"
                        style={{ "max-width": maxWidth + "px" }}
                        alt={content.body}
                        onError={this.onImageError}
                        onLoad={this.onImageLoad}
                        onMouseEnter={this.onImageEnter}
                        onMouseLeave={this.onImageLeave} />
                </div>
            </a>
        );

        return (
            <span className="mx_MImageBody" ref="body">
                { thumbUrl && !this.state.imgError ? thumbnail : '' }
                <MFileBody {...this.props} decryptedBlob={this.state.decryptedBlob} />
            </span>
      );
    }

    render() {
        const content = this.props.mxEvent.getContent();

        if (this.state.error !== null) {
            return (
                <span className="mx_MImageBody" ref="body">
                    <img src="img/warning.svg" width="16" height="16" />
                    { _t("Error decrypting image") }
                </span>
            );
        }

        if (content.file !== undefined && this.state.decryptedUrl === null) {
            // Need to decrypt the attachment
            // The attachment is decrypted in componentDidMount.
            // For now add an img tag with a spinner.
            return (
                <span className="mx_MImageBody" ref="body">
                    <div className="mx_MImageBody_thumbnail" ref="image" style={{
                        "display": "flex",
                        "alignItems": "center",
                        "width": "100%",
                    }}>
                        <img src="img/spinner.gif" alt={content.body} width="32" height="32" style={{
                            "margin": "auto",
                        }} />
                    </div>
                </span>
            );
        }

        const contentUrl = this._getContentUrl();
        let thumbUrl;
        if (this._isGif() && SettingsStore.getValue("autoplayGifsAndVideos")) {
          thumbUrl = contentUrl;
        } else {
          thumbUrl = this._getThumbUrl();
        }

        return this._messageContent(contentUrl, thumbUrl, content);
    }
}