import {startsWith, getFileExtension} from '../utils/string';
import {getUrlFromUri} from '../utils/uri';
import {fileContentTypes} from './filesLoader';
import {urlContentTypes} from './urlsLoader';
/**
* JSON text loader.
*/
export class JSONTextLoader {
/**
* Loading flag.
*
* @type {boolean}
*/
#isLoading = false;
/**
* Set the loader options.
*
* @param {object} _opt The input options.
*/
setOptions(_opt) {
// does nothing
}
/**
* Is the load ongoing?
*
* @returns {boolean} True if loading.
*/
isLoading() {
return this.#isLoading;
}
/**
* Load data.
*
* @param {object} text The input text.
* @param {string} origin The data origin.
* @param {number} index The data index.
*/
load(text, origin, index) {
// set loading flag
this.#isLoading = true;
this.onloadstart({
source: origin
});
try {
this.onprogress({
lengthComputable: true,
loaded: 100,
total: 100,
index: index,
source: origin
});
const data = {
data: text,
source: origin
};
// only expecting one item
this.onloaditem(data);
this.onload(data);
} catch (error) {
this.onerror({
error: error,
source: origin
});
} finally {
// reset loading flag
this.#isLoading = false;
this.onloadend({
source: origin
});
}
}
/**
* Abort load: pass to listeners.
*/
abort() {
// reset loading flag
this.#isLoading = false;
// call listeners
this.onabort({});
this.onloadend({});
}
/**
* Check if the loader can load the provided file.
* True if the file has a 'json' extension.
*
* @param {File} file The file to check.
* @returns {boolean} True if the file can be loaded.
*/
canLoadFile(file) {
const ext = getFileExtension(file.name);
return (ext === 'json');
}
/**
* Check if the loader can load the provided url.
* True if one of the folowing conditions is true:
* - the `options.forceLoader` is 'json',
* - the `options.requestHeaders` contains a 'Accept: application/json' or
* 'Accept: application/dicom+json',
* - the url has a 'json' extension.
*
* @param {string} url The url to check.
* @param {object} [options] Optional url request options.
* @returns {boolean} True if the url can be loaded.
*/
canLoadUrl(url, options) {
// check options
if (typeof options !== 'undefined') {
// check options.forceLoader
if (typeof options.forceLoader !== 'undefined' &&
options.forceLoader === 'json') {
return true;
}
// check options.requestHeaders for 'Accept'
if (typeof options.requestHeaders !== 'undefined') {
const isNameAccept = function (element) {
return element.name === 'Accept';
};
const acceptHeader = options.requestHeaders.find(isNameAccept);
if (typeof acceptHeader !== 'undefined') {
// starts with 'application/json' or 'application/dicom+json
return startsWith(acceptHeader.value, 'application/json') ||
startsWith(acceptHeader.value, 'application/dicom+json');
}
}
}
const urlObjext = getUrlFromUri(url);
const ext = getFileExtension(urlObjext.pathname);
return (ext === 'json');
}
/**
* Check if the loader can load the provided memory object.
*
* @param {object} mem The memory object.
* @returns {boolean} True if the object can be loaded.
*/
canLoadMemory(mem) {
const contentType = mem['Content-Type'];
if (typeof contentType !== 'undefined' &&
contentType.startsWith('application/json')) {
return true;
}
if (typeof mem.filename !== 'undefined') {
const tmpFile = new File(['from memory'], mem.filename);
return this.canLoadFile(tmpFile);
}
return false;
}
/**
* Get the file content type needed by the loader.
*
* @returns {number} One of the 'fileContentTypes'.
*/
loadFileAs() {
return fileContentTypes.Text;
}
/**
* Get the url content type needed by the loader.
*
* @returns {number} One of the 'urlContentTypes'.
*/
loadUrlAs() {
return urlContentTypes.Text;
}
/**
* Handle a load start event.
* Default does nothing.
*
* @param {object} _event The load start event.
*/
onloadstart(_event) {}
/**
* Handle a progress event.
* Default does nothing.
*
* @param {object} _event The load progress event.
*/
onprogress(_event) {}
/**
* Handle a load item event.
* Default does nothing.
*
* @param {object} _event The load item event fired
* when a file item has been loaded successfully.
*/
onloaditem(_event) {}
/**
* Handle a load event.
* Default does nothing.
*
* @param {object} _event The load event fired
* when a file has been loaded successfully.
*/
onload(_event) {}
/**
* Handle an load end event.
* Default does nothing.
*
* @param {object} _event The load end event fired
* when a file load has completed, successfully or not.
*/
onloadend(_event) {}
/**
* Handle an error event.
* Default does nothing.
*
* @param {object} _event The error event.
*/
onerror(_event) {}
/**
* Handle an abort event.
* Default does nothing.
*
* @param {object} _event The abort event.
*/
onabort(_event) {}
} // class JSONTextLoader