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browser_files.ts
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browser_files.ts
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/**
* @license
* Copyright 2018 Google LLC. 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.
* =============================================================================
*/
/**
* IOHandlers related to files, such as browser-triggered file downloads,
* user-selected files in browser.
*/
import {ENV} from '../environment';
import {basename, concatenateArrayBuffers, getModelArtifactsInfoForJSON} from './io_utils';
import {IORouter, IORouterRegistry} from './router_registry';
import {IOHandler, ModelArtifacts, ModelJSON, SaveResult, WeightsManifestConfig, WeightsManifestEntry} from './types';
const DEFAULT_FILE_NAME_PREFIX = 'model';
const DEFAULT_JSON_EXTENSION_NAME = '.json';
const DEFAULT_WEIGHT_DATA_EXTENSION_NAME = '.weights.bin';
export class BrowserDownloads implements IOHandler {
private readonly modelTopologyFileName: string;
private readonly weightDataFileName: string;
private readonly jsonAnchor: HTMLAnchorElement;
private readonly weightDataAnchor: HTMLAnchorElement;
static readonly URL_SCHEME = 'downloads://';
constructor(fileNamePrefix?: string) {
if (!ENV.get('IS_BROWSER')) {
// TODO(cais): Provide info on what IOHandlers are available under the
// current environment.
throw new Error(
'browserDownloads() cannot proceed because the current environment ' +
'is not a browser.');
}
if (fileNamePrefix.startsWith(BrowserDownloads.URL_SCHEME)) {
fileNamePrefix = fileNamePrefix.slice(BrowserDownloads.URL_SCHEME.length);
}
if (fileNamePrefix == null || fileNamePrefix.length === 0) {
fileNamePrefix = DEFAULT_FILE_NAME_PREFIX;
}
this.modelTopologyFileName = fileNamePrefix + DEFAULT_JSON_EXTENSION_NAME;
this.weightDataFileName =
fileNamePrefix + DEFAULT_WEIGHT_DATA_EXTENSION_NAME;
}
async save(modelArtifacts: ModelArtifacts): Promise<SaveResult> {
const weightsURL = window.URL.createObjectURL(new Blob(
[modelArtifacts.weightData], {type: 'application/octet-stream'}));
if (modelArtifacts.modelTopology instanceof ArrayBuffer) {
throw new Error(
'BrowserDownloads.save() does not support saving model topology ' +
'in binary formats yet.');
} else {
const weightsManifest: WeightsManifestConfig = [{
paths: ['./' + this.weightDataFileName],
weights: modelArtifacts.weightSpecs
}];
const modelTopologyAndWeightManifest: ModelJSON = {
modelTopology: modelArtifacts.modelTopology,
format: modelArtifacts.format,
generatedBy: modelArtifacts.generatedBy,
convertedBy: modelArtifacts.convertedBy,
weightsManifest
};
const modelTopologyAndWeightManifestURL =
window.URL.createObjectURL(new Blob(
[JSON.stringify(modelTopologyAndWeightManifest)],
{type: 'application/json'}));
// If anchor elements are not provided, create them without attaching them
// to parents, so that the downloaded file names can be controlled.
const jsonAnchor = this.jsonAnchor == null ? document.createElement('a') :
this.jsonAnchor;
jsonAnchor.download = this.modelTopologyFileName;
jsonAnchor.href = modelTopologyAndWeightManifestURL;
// Trigger downloads by calling the `click` methods on the download
// anchors.
jsonAnchor.click();
if (modelArtifacts.weightData != null) {
const weightDataAnchor = this.weightDataAnchor == null ?
document.createElement('a') :
this.weightDataAnchor;
weightDataAnchor.download = this.weightDataFileName;
weightDataAnchor.href = weightsURL;
weightDataAnchor.click();
}
return {modelArtifactsInfo: getModelArtifactsInfoForJSON(modelArtifacts)};
}
}
}
class BrowserFiles implements IOHandler {
private readonly files: File[];
constructor(files: File[]) {
if (files == null || files.length < 1) {
throw new Error(
`When calling browserFiles, at least 1 file is required, ` +
`but received ${files}`);
}
this.files = files;
}
async load(): Promise<ModelArtifacts> {
const jsonFile = this.files[0];
const weightFiles = this.files.slice(1);
return new Promise<ModelArtifacts>((resolve, reject) => {
const jsonReader = new FileReader();
jsonReader.onload = (event: Event) => {
// tslint:disable-next-line:no-any
const modelJSON = JSON.parse((event.target as any).result) as ModelJSON;
const modelTopology = modelJSON.modelTopology;
if (modelTopology == null) {
reject(new Error(
`modelTopology field is missing from file ${jsonFile.name}`));
return;
}
if (weightFiles.length === 0) {
resolve({modelTopology});
}
const weightsManifest = modelJSON.weightsManifest;
if (weightsManifest == null) {
reject(new Error(
`weightManifest field is missing from file ${jsonFile.name}`));
return;
}
let pathToFile: {[path: string]: File};
try {
pathToFile =
this.checkManifestAndWeightFiles(weightsManifest, weightFiles);
} catch (err) {
reject(err);
return;
}
const weightSpecs: WeightsManifestEntry[] = [];
const paths: string[] = [];
const perFileBuffers: ArrayBuffer[] = [];
weightsManifest.forEach(weightsGroup => {
weightsGroup.paths.forEach(path => {
paths.push(path);
perFileBuffers.push(null);
});
weightSpecs.push(...weightsGroup.weights);
});
weightsManifest.forEach(weightsGroup => {
weightsGroup.paths.forEach(path => {
const weightFileReader = new FileReader();
weightFileReader.onload = (event: Event) => {
// tslint:disable-next-line:no-any
const weightData = (event.target as any).result as ArrayBuffer;
const index = paths.indexOf(path);
perFileBuffers[index] = weightData;
if (perFileBuffers.indexOf(null) === -1) {
resolve({
modelTopology,
weightSpecs,
weightData: concatenateArrayBuffers(perFileBuffers),
});
}
};
weightFileReader.onerror = error =>
reject(`Failed to weights data from file of path '${path}'.`);
weightFileReader.readAsArrayBuffer(pathToFile[path]);
});
});
};
jsonReader.onerror = error => reject(
`Failed to read model topology and weights manifest JSON ` +
`from file '${jsonFile.name}'. BrowserFiles supports loading ` +
`Keras-style tf.Model artifacts only.`);
jsonReader.readAsText(jsonFile);
});
}
/**
* Check the compatibility between weights manifest and weight files.
*/
private checkManifestAndWeightFiles(
manifest: WeightsManifestConfig, files: File[]): {[path: string]: File} {
const basenames: string[] = [];
const fileNames = files.map(file => basename(file.name));
const pathToFile: {[path: string]: File} = {};
for (const group of manifest) {
group.paths.forEach(path => {
const pathBasename = basename(path);
if (basenames.indexOf(pathBasename) !== -1) {
throw new Error(
`Duplicate file basename found in weights manifest: ` +
`'${pathBasename}'`);
}
basenames.push(pathBasename);
if (fileNames.indexOf(pathBasename) === -1) {
throw new Error(
`Weight file with basename '${pathBasename}' is not provided.`);
} else {
pathToFile[path] = files[fileNames.indexOf(pathBasename)];
}
});
}
if (basenames.length !== files.length) {
throw new Error(
`Mismatch in the number of files in weights manifest ` +
`(${basenames.length}) and the number of weight files provided ` +
`(${files.length}).`);
}
return pathToFile;
}
}
export const browserDownloadsRouter: IORouter = (url: string|string[]) => {
if (!ENV.get('IS_BROWSER')) {
return null;
} else {
if (!Array.isArray(url) && url.startsWith(BrowserDownloads.URL_SCHEME)) {
return browserDownloads(url.slice(BrowserDownloads.URL_SCHEME.length));
} else {
return null;
}
}
};
IORouterRegistry.registerSaveRouter(browserDownloadsRouter);
/**
* Creates an IOHandler that triggers file downloads from the browser.
*
* The returned `IOHandler` instance can be used as model exporting methods such
* as `tf.Model.save` and supports only saving.
*
* ```js
* const model = tf.sequential();
* model.add(tf.layers.dense(
* {units: 1, inputShape: [10], activation: 'sigmoid'}));
* const saveResult = await model.save('downloads://mymodel'));
* // This will trigger downloading of two files:
* // 'mymodel.json' and 'mymodel.weights.bin'.
* console.log(saveResult);
* ```
*
* @param fileNamePrefix Prefix name of the files to be downloaded. For use with
* `tf.Model`, `fileNamePrefix` should follow either of the following two
* formats:
* 1. `null` or `undefined`, in which case the default file
* names will be used:
* - 'model.json' for the JSON file containing the model topology and
* weights manifest.
* - 'model.weights.bin' for the binary file containing the binary weight
* values.
* 2. A single string or an Array of a single string, as the file name prefix.
* For example, if `'foo'` is provided, the downloaded JSON
* file and binary weights file will be named 'foo.json' and
* 'foo.weights.bin', respectively.
* @param config Additional configuration for triggering downloads.
* @returns An instance of `BrowserDownloads` `IOHandler`.
*/
/** @doc {heading: 'Models', subheading: 'Loading', namespace: 'io'} */
export function browserDownloads(fileNamePrefix = 'model'): IOHandler {
return new BrowserDownloads(fileNamePrefix);
}
/**
* Creates an IOHandler that loads model artifacts from user-selected files.
*
* This method can be used for loading from files such as user-selected files
* in the browser.
* When used in conjunction with `tf.loadModel`, an instance of `tf.Model`
* (Keras-style) can be constructed from the loaded artifacts.
*
* ```js
* // Note: This code snippet won't run properly without the actual file input
* // elements in the HTML DOM.
*
* // Suppose there are two HTML file input (`<input type="file" ...>`)
* // elements.
* const uploadJSONInput = document.getElementById('upload-json');
* const uploadWeightsInput = document.getElementById('upload-weights');
* const model = await tfl.loadModel(tf.io.browserFiles(
* [uploadJSONInput.files[0], uploadWeightsInput.files[0]]));
* ```
*
* @param files `File`s to load from. Currently, this function supports only
* loading from files that contain Keras-style models (i.e., `tf.Model`s), for
* which an `Array` of `File`s is expected (in that order):
* - A JSON file containing the model topology and weight manifest.
* - Optionally, One or more binary files containing the binary weights.
* These files must have names that match the paths in the `weightsManifest`
* contained by the aforementioned JSON file, or errors will be thrown
* during loading. These weights files have the same format as the ones
* generated by `tensorflowjs_converter` that comes with the `tensorflowjs`
* Python PIP package. If no weights files are provided, only the model
* topology will be loaded from the JSON file above.
* @returns An instance of `Files` `IOHandler`.
*/
/** @doc {heading: 'Models', subheading: 'Loading', namespace: 'io'} */
export function browserFiles(files: File[]): IOHandler {
return new BrowserFiles(files);
}