Needful Program Management

    kneecap

    1.6.4 • Public • Published

    KC = kneecap

    Testing

    npm test
    

    How it works

    A KC instance only allows separate endpoints per http request/response. A single callback can be attached to each endpoint, which must return a promise.

    Gotchas

    • You should make sure headers['content-length'] is valid (or removed) when changing the request's (or response's) body, otherwise the data may end up truncated.
    • Getting the preview is a lot faster than getting the full body. Use request.getPreivew() where possible.

    Examples

    Change request headers

            icapServer.requestHandler('/request', function(request) {
                return request.getRequestHeaders()
                    .then(headers => {
                        return {
                            requestHeaders: headers.replace(myHeaderName, `${myHeaderName}-Changed`)
                        };
                    });
            });

    Change request body

            icapServer.requestHandler('/request', function(request) {
                return Promise.all([request.getRequestHeaders(), request.getRawBody()])
                    .then(results => {
                        const [requestHeaders, requestBody] = results;
                        const diff = expectedBodyValue.length - myFormValue.length;
                        const oldContentLength = Number(requestHeaders.match(/content-length: (\d+)/i)[1]);
                        return {
                            requestBody: Buffer.from(requestBody.toString().replace(myFormValue, expectedBodyValue)),
                            requestHeaders: requestHeaders.replace(/content-length: (\d+)/i, `Content-Length: ${oldContentLength + diff}`)
                        };
                    });
            });

    Don't change anything

            icapServer.requestHandler('/request', function(request) {
                return Promise.all([request.getRequestHeaders(), request.getRawBody()])
                    .then(results => {
                        const [requestHeaders, requestBody] = results;
                        console.log('Got request', requestHeaders, requestBody);
                        return;
                    });
            });

    Set request options

            icapServer.requestHandler('/request', {
                previewBytes: 128,
                transfer: {
                    complete: ['html', 'js'],
                    ignore: ['jpg', 'ogg', 'mp4', 'gif', 'gifv'],
                    preview: ['*'],
                }
            }, function(request) {
                return Promise.resolve(request.getPreview())
                    .then(previewBody => {
                        console.log('preview', previewBody.toString());
                    });
            });

    API

    Server instance

    listen

    Accepts the same params as node.js's net server.listen, except for the final callback.

    Returns a promise which resolves when listening.

    const kneecap = require('kneecap');
     
    const kc = kneecap();
    kc.listen(8008)
        .then(() => {
            console.log('listening');
        });

    close

    Stops the server from accepting new connections. Resolves when remaining connections have been closed.

    kc.close()
        .then(() => {
            console.log('icap server closed');
        });

    events

    Events are emitted on this emitter.

    kc.events.on('error', err => {
        console.log('icap server error', err);
    });

    requestHandler

    Adds a REQMOD handler.

    server.requestHandler(path[, options], callback)

    The path must be a string where icap REQMOD requests will be listened to.

    The options object, when included, will specify the OPTIONS response for the path endpoint. Supported options:

    • transfer object, which must contain at least one child with the all ['*'] setting
      • complete array, will be sent as Transfer-Complete, i.e. ['html', 'js']
      • ignore array, will be sent as Transfer-Ignore, i.e. ['jpg', 'jpeg', 'swf', 'mp4']
      • preview array, will be sent as Transfer-Preview, i.e. ['*']
    • previewBytes integer, how long should the preview be (where available), in bytes.
    kc.requestHandler('/request', {
        previewBytes: 128,
        transfer: {
            complete: ['html', 'js'],
            ignore: ['jpg', 'ogg', 'mp4', 'gif', 'gifv'],
            preview: ['*'],
        }
    }, handleRequest);

    responseHandler

    Adds a RESPMOD handler. Same usage as requestHandler.


    Request

    IcapRequest passed to requestHandler and responseHandler methods.

    hasRequestHeaders

    Synchronous, returns a boolean whether the icap request has request headers.

    getRequestHeaders

    Returns a promise which resolves to the request headers as a String, most likely separated by \r\n.

    getRawRequestHeaders

    Returns a promise which resolves to the request headers as a Buffer.

    hasResponseHeaders

    Synchronous, returns a boolean whether the icap request has response headers.

    getResponseHeaders

    Returns a promise which resolves to the response headers as a String, most likely separated by \r\n.

    getRawResponseHeaders

    Returns a promise which resolves to the response headers as a Buffer.

    hasBody

    Synchronous, returns a boolean whether the icap request has a request or response body (depends on REQMOD/RESPMOD handler type).

    hasPreview

    Returns a promise which resolves to a boolean whether the request has a body preview.

    getPreview

    Returns a promise which resolves to the request/response body preview as a buffer (depends on REQMOD/RESPMOD handler type). The promise may be resolved synchronously, so call Promise.resolve(request.getPreview()) as a best practice.

    getRawBody

    Returns a promise which resolves to the request/response body as a buffer (depends on REQMOD/RESPMOD handler type).

    getRequest

    Returns a promise which resolves to an http.ClientRequest.


    Respond

    To respond to an icap Request, the request handler must return a promise which resolves to either:

    • falsey value (undefined, null, false), which will not modify the request, forwarding it as is. If Allow: 204 is sent by the icap client, then 204 No Content will be returned. Otherwise, the request data will be sent back unchanged.
    kc.requestHandler('/request', function(request) {
        return null;
    });
    • object containing any combination of requestHeaders:String, requestBody:Buffer, responseHeaders:String, responseBody:Buffer. You must only include one body in the response.
    kc.requestHandler('/request', function(request) {
        return Promise.all([request.getRequestHeaders(), request.getRawBody()])
            .then(results => {
                const [requestHeaders, requestBody] = results;
                return {
                    requestBody: Buffer.from('foo=bar'),
                    requestHeaders: requestHeaders
                };
            });
    });

    License

    Apache 2.0

    Copyright 2016 Universal Basket

    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.

    Keywords

    Install

    npm i kneecap

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    1

    Version

    1.6.4

    License

    UB

    Last publish

    Collaborators

    • randunel