@sitemark/exifr/dist/esm/xmp-parser.js

📑 The fastest and most versatile JavaScript EXIF reading library.

import DOMParser from './dom-parser.js';

/* Based on https://github.com/mattiasw/ExifReader/blob/master/src/xmp-tags.js
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/. */

var XMPParser = {
    read
};

const tagTypes = {

    // DJI
    'drone-dji:CamReverse': 'bool',
    'drone-dji:GimbalReverse': 'bool',

    // CRS
    'crs:Version': 'string',

    // Camera
    'Camera:IsNormalized': 'bool',
};

function read(xmpString) {
    try {
        const doc = getDocument(xmpString.replace(/\0/g, ""));
        const rdf = getRDF(doc);

        const xmp = parseXMPObject(convertToObject(rdf, true));
        Object.keys(xmp).forEach((key) => {
            xmp[key] = parseValue(key, xmp[key]);
        });
        return xmp;
    } catch (error) {
        return {};
    }
}

function parseValue(key, value) {
    if (value instanceof Array) {
        return value.map((val) => parseValue(key, val));
    } else if (value instanceof Object && 'value' in value) {
        return {
            ...value,
            value: parseValue(key, value.value),
        };
    } else if (tagTypes[key]) {
        if (tagTypes[key] === 'bool') {
            if (['True', 'true', '1'].includes(value)) {
                return true;
            } else if (['False', 'false', '0'].includes(value)) {
                return false;
            }
            throw new Error(`Unknown value ${value} for key ${key} to be parsed as bool.`)
        } else if (tagTypes[key] === 'string') {
            return value;
        }
    } else if (!isNaN(value) && value !== '') {
        return Number(value);
    } else if (['False', 'false'].includes(value)) {
        return false;
    } else if (['True', 'true'].includes(value)) {
        return true;
    }
    return value
}

function getDocument(xmlSource) {
    const Parser = DOMParser.get();
    if (!Parser) {
        console.warn('Warning: DOMParser is not available. It is needed to be able to parse XMP tags.'); // eslint-disable-line no-console
        throw new Error();
    }

    const domParser = new Parser();
    const doc = domParser.parseFromString(xmlSource, 'application/xml');

    if (doc.documentElement.nodeName === 'parsererror') {
        throw new Error(doc.documentElement.textContent);
    }

    return doc;
}

function getRDF(node) {
    for (let i = 0; i < node.childNodes.length; i++) {
        if (node.childNodes[i].tagName === 'x:xmpmeta') {
            return getRDF(node.childNodes[i]);
        }
        if (node.childNodes[i].tagName === 'rdf:RDF') {
            return node.childNodes[i];
        }
    }

    throw new Error();
}

function convertToObject(node, isTopNode = false) {
    const childNodes = getChildNodes(node);

    if (hasTextOnlyContent(childNodes)) {
        if (isTopNode) {
            return {};
        }
        return getTextValue(childNodes[0]);
    }

    return getElementsFromNodes(childNodes);
}

function getChildNodes(node) {
    const elements = [];

    for (let i = 0; i < node.childNodes.length; i++) {
        elements.push(node.childNodes[i]);
    }

    return elements;
}

function hasTextOnlyContent(nodes) {
    return (nodes.length === 1) && (nodes[0].nodeName === '#text');
}

function getTextValue(node) {
    return node.nodeValue;
}

function getElementsFromNodes(nodes) {
    const elements = {};

    nodes.forEach((node) => {
        if (isElement(node)) {
            const nodeElement = getElementFromNode(node);

            if (elements[node.nodeName] !== undefined) {
                if (!Array.isArray(elements[node.nodeName])) {
                    elements[node.nodeName] = [elements[node.nodeName]];
                }
                elements[node.nodeName].push(nodeElement);
            } else {
                elements[node.nodeName] = nodeElement;
            }
        }
    });

    return elements;
}

function isElement(node) {
    return (node.nodeName) && (node.nodeName !== '#text');
}

function getElementFromNode(node) {
    return {
        attributes: getAttributes(node),
        value: convertToObject(node)
    };
}

function getAttributes(element) {
    const attributes = {};

    for (let i = 0; i < element.attributes.length; i++) {
        attributes[element.attributes[i].nodeName] = decodeURIComponent(escape(element.attributes[i].value));
    }

    return attributes;
}

function parseXMPObject(xmpObject) {
    const tags = {};

    if (typeof xmpObject === 'string') {
        return xmpObject;
    }

    for (const nodeName in xmpObject) {
        let nodes = xmpObject[nodeName];

        if (!Array.isArray(nodes)) {
            nodes = [nodes];
        }

        nodes.forEach((node) => {
            Object.assign(tags, parseNodeAttributesAsTags(node.attributes));
            if (typeof node.value === 'object') {
                Object.assign(tags, parseNodeChildrenAsTags(node.value));
            }
        });
    }

    // Assign value directly to key to filter out attributes and description
    for (const key of Object.keys(tags)) {
        tags[key] = tags[key].value;
    }

    return tags;
}

function parseNodeAttributesAsTags(attributes) {
    const tags = {};

    for (const name in attributes) {
        if (isTagAttribute(name)) {
            tags[getLocalName(name)] = {
                value: attributes[name],
                attributes: {},
                description: getDescription(attributes[name], name)
            };
        }
    }

    return tags;
}

function isTagAttribute(name) {
    return (name !== 'rdf:parseType') && (!isNamespaceDefinition(name));
}

function isNamespaceDefinition(name) {
    return name.split(':')[0] === 'xmlns';
}

function getLocalName(name) {
    // return name.split(':')[1];
    // We want to keep full name to avoid overwriting other tags when merging
    return name;
}

function getDescription(value, name = undefined) {
    if (Array.isArray(value)) {
        return getDescriptionOfArray(value);
    }
    if (typeof value === 'object') {
        return getDescriptionOfObject(value);
    }

    try {
        return decodeURIComponent(escape(value));
    } catch (error) {
        return value;
    }
}

function getDescriptionOfArray(value) {
    return value.map((item) => {
        if (item.value !== undefined) {
            return getDescription(item.value);
        }
        return getDescription(item);
    }).join(', ');
}

function getDescriptionOfObject(value) {
    const descriptions = [];

    for (const key in value) {
        descriptions.push(`${getClearTextKey(key)}: ${value[key].value}`);
    }

    return descriptions.join('; ');
}

function getClearTextKey(key) {
    if (key === 'CiAdrCity') {
        return 'CreatorCity';
    }
    if (key === 'CiAdrCtry') {
        return 'CreatorCountry';
    }
    if (key === 'CiAdrExtadr') {
        return 'CreatorAddress';
    }
    if (key === 'CiAdrPcode') {
        return 'CreatorPostalCode';
    }
    if (key === 'CiAdrRegion') {
        return 'CreatorRegion';
    }
    if (key === 'CiEmailWork') {
        return 'CreatorWorkEmail';
    }
    if (key === 'CiTelWork') {
        return 'CreatorWorkPhone';
    }
    if (key === 'CiUrlWork') {
        return 'CreatorWorkUrl';
    }
    return key;
}

function parseNodeChildrenAsTags(children) {
    const tags = {};

    for (const name in children) {
        if (!isNamespaceDefinition(name)) {
            tags[getLocalName(name)] = parseNodeAsTag(children[name], name);
        }
    }

    return tags;
}

function parseNodeAsTag(node, name) {
    if (hasNestedSimpleRdfDescription(node)) {
        return parseNodeAsSimpleRdfDescription(node, name);
    } else if (hasNestedStructureRdfDescription(node)) {
        return parseNodeAsStructureRdfDescription(node, name);
    } else if (isCompactStructure(node)) {
        return parseNodeAsCompactStructure(node, name);
    } else if (isArray(node)) {
        return parseNodeAsArray(node, name);
    }
    return parseNodeAsSimpleValue(node, name);
}

function hasNestedSimpleRdfDescription(node) {
    return ((node.attributes['rdf:parseType'] === 'Resource') && (node.value['rdf:value'] !== undefined))
        || ((node.value['rdf:Description'] !== undefined) && (node.value['rdf:Description'].value['rdf:value'] !== undefined));
}

function parseNodeAsSimpleRdfDescription(node, name) {
    const attributes = parseNodeAttributes(node);

    if (node.value['rdf:Description'] !== undefined) {
        node = node.value['rdf:Description'];
    }

    Object.assign(attributes, parseNodeAttributes(node), parseNodeChildrenAsAttributes(node));

    const value = parseRdfValue(node);

    return {
        value,
        attributes,
        description: getDescription(value, name)
    };
}

function parseNodeAttributes(node) {
    const attributes = {};

    for (const name in node.attributes) {
        if ((name !== 'rdf:parseType') && (name !== 'rdf:resource') && (!isNamespaceDefinition(name))) {
            attributes[getLocalName(name)] = node.attributes[name];
        }
    }

    return attributes;
}

function parseNodeChildrenAsAttributes(node) {
    const attributes = {};

    for (const name in node.value) {
        if ((name !== 'rdf:value') && (!isNamespaceDefinition(name))) {
            attributes[getLocalName(name)] = node.value[name].value;
        }
    }

    return attributes;
}

function parseRdfValue(node) {
    return getURIValue(node.value['rdf:value']) || node.value['rdf:value'].value;
}

function hasNestedStructureRdfDescription(node) {
    return (node.attributes['rdf:parseType'] === 'Resource')
        || ((node.value['rdf:Description'] !== undefined) && (node.value['rdf:Description'].value['rdf:value'] === undefined));
}

function parseNodeAsStructureRdfDescription(node, name) {
    const tag = {
        value: {},
        attributes: {}
    };

    if (node.value['rdf:Description'] !== undefined) {
        Object.assign(tag.value, parseNodeAttributesAsTags(node.value['rdf:Description'].attributes));
        Object.assign(tag.attributes, parseNodeAttributes(node));
        node = node.value['rdf:Description'];
    }

    Object.assign(tag.value, parseNodeChildrenAsTags(node.value));

    tag.description = getDescription(tag.value, name);

    return tag;
}

function isCompactStructure(node) {
    return (Object.keys(node.value).length === 0)
        && (node.attributes['rdf:resource'] === undefined);
}

function parseNodeAsCompactStructure(node, name) {
    const value = parseNodeAttributesAsTags(node.attributes);

    return {
        value,
        attributes: {},
        description: getDescription(value, name)
    };
}

function isArray(node) {
    return getArrayChild(node.value) !== undefined;
}

function getArrayChild(value) {
    return value['rdf:Bag'] || value['rdf:Seq'] || value['rdf:Alt'];
}

function parseNodeAsArray(node, name) {
    let items = getArrayChild(node.value).value['rdf:li'];
    const attributes = parseNodeAttributes(node);
    const value = [];

    if (!Array.isArray(items)) {
        items = [items];
    }

    items.forEach((item) => {
        value.push(parseArrayValue(item));
    });

    return {
        value,
        attributes,
        description: getDescription(value, name)
    };
}

function parseArrayValue(item) {
    if (hasNestedSimpleRdfDescription(item)) {
        return parseNodeAsSimpleRdfDescription(item);
    }

    if (hasNestedArrayValue(item)) {
        return parseNodeChildrenAsTags(item.value);
    }

    return {
        value: item.value,
        attributes: parseNodeAttributes(item),
        description: getDescription(item.value)
    };
}

function hasNestedArrayValue(node) {
    return node.attributes['rdf:parseType'] === 'Resource';
}

function parseNodeAsSimpleValue(node, name) {
    const value = getURIValue(node) || parseXMPObject(node.value);

    return {
        value,
        attributes: parseNodeAttributes(node),
        description: getDescription(value, name)
    };
}

function getURIValue(node) {
    return node.attributes && node.attributes['rdf:resource'];
}

export { XMPParser as default };