@sap/xsodata/lib/utils/batch/batchParser.js

Expose data from a HANA database as OData V2 service with help of .xsodata files.

'use strict';

const utils = require('./../utils');
const batchObjects = require('./batchObjects');

exports.getBoundary = function (headerValue) {
    const l = headerValue.split(';');

    for (const element of l) {
        const ll = element.split('=');
        if (ll[0].trim() === 'boundary') {
            return ll[1];
        }
    }
};

function readAppHttp(batchContent, boundary) {
    const headers = {};
    const payload = [];

    let state = 0; //read url
    const url = batchContent.readLine();

    state = 1; //read header
    let line = batchContent.lookLine();

    while (
        line !== null &&
        line !== undefined &&
        line.indexOf(boundary) !== 0
    ) {
        if (state === 1) {
            if (line.length === 0) {
                state = 2; //read body
                batchContent.inc();
            } else {
                const h = readHeader(line);
                headers[h.name] = h.value;
                batchContent.inc();
            }
        } else if (state === 2) {
            payload.push(line);
            batchContent.inc();
        }
        line = batchContent.lookLine();
    }
    if (line === undefined) {
        throw new Error(
            'Invalid boundary while parsing batch request. Expect boundary ' +
                boundary
        );
    }

    return new batchObjects.AppHttp(url, headers, payload);
}

function parsePart(batchContent, boundary) {
    const boundaryNext = boundary;
    const boundaryEnd = boundary + '--';
    const headers = {};
    let content;

    let state = 1; //read header
    let line = batchContent.lookLine();

    while (
        line !== null &&
        line !== undefined &&
        line !== boundaryNext &&
        line !== boundaryEnd
    ) {
        if (state === 1) {
            if (line.length === 0) {
                state = 2; //read body
                batchContent.inc();
            } else {
                const h = readHeader(line);
                headers[h.name] = h.value;
                batchContent.inc();
            }
        } else if (state === 2) {
            if (!headers['content-type']) {
                throw new Error('Missing header "content-type" in batch part');
            } else if (headers['content-type'] === 'application/http') {
                content = readAppHttp(batchContent, boundary);
            } else if (
                utils.startsWith(headers['content-type'], 'multipart/mixed;')
            ) {
                const changeSetBoundary = exports.getBoundary(
                    headers['content-type']
                );
                content = parseBatch(
                    batchContent,
                    changeSetBoundary,
                    'changeset'
                );
            } else {
                //TODO not supported
            }
        }
        line = batchContent.lookLine();
    }
    if (line === undefined) {
        throw new Error(
            'Invalid boundary while parsing batch request. Expect boundary ' +
                boundary
        );
    }

    return content;
}

function readHeader(line) {
    const colPos = line.indexOf(':');
    if (colPos === -1) {
        throw new Error('Invalid header "content-type" in batch part');
    }

    const s0 = line.substr(0, colPos);
    const s1 = line.substr(colPos + 1);
    return {
        name: s0.toLowerCase(),
        value: s1.trim(),
    };
}

function parseBatch(content, boundary, type) {
    const boundaryNext = '--' + boundary;
    const boundaryEnd = '--' + boundary + '--';

    const batch = new batchObjects.Batch(type);

    let part;

    let line = content.readLine();
    while (line !== null && line !== undefined && line !== boundaryNext) {
        //read lines before first boundary
        line = content.readLine();
    }
    if (line === undefined) {
        throw new Error('Invalid boundary while parsing batch request');
    }
    //line is now read boundary
    line = content.lookLine(); //read line behind

    while (line !== null && line !== undefined && line !== boundaryEnd) {
        part = parsePart(content, boundaryNext);
        batch.parts.push(part);
        line = content.lookLine(); //now on boundary
        if (line === boundaryNext) {
            line = content.readLine(); //consume boundaryNext
        }
    }

    content.readLine(); //consume boundaryEnd
    line = content.lookLine(); //read line behind
    while (line !== null && line !== undefined && line.length === 0) {
        //read empty lines after first boundaryend
        content.readLine();
        line = content.lookLine();
    }

    return batch;
}

exports.convertBatch = function (payload, boundary) {
    return parseBatch(
        new batchObjects.BatchContent(payload),
        boundary,
        'batch'
    );
};