49 lines
1.8 KiB
TypeScript
49 lines
1.8 KiB
TypeScript
const supportFiles = [{type:'image/png',ext:'png'},{type:'image/jpeg',ext:'jpeg'},{type:'image/gif',ext:'gif'},{type:'image/webp',ext:'webp'},{type:'image/jpg',ext:'jpg'},{type:'image/x-icon',ext:'ico'},{type:'application/x-ico',ext:'ico'},{type:'image/vnd.microsoft.icon',ext:'ico'}]
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const supportFile = 'image/png,image/jpeg,image/gif,image/webp,image/jpg,image/x-icon,application/x-ico,image/vnd.microsoft.icon'
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// 字符串编码
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export function randomString(value: number) {
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let baseStr = 'Aa0Bb1Cc2Dd3Ee4Ff5Gg6Hh7Ii8Jj9KkLlMmNnOoPpQqRrSsTtUuVvWwXxYyZz';
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const chars = baseStr.split('');
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let maxPos = baseStr.length;
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const uuid = [];
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let q = value;
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for(;q > 0;) {
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let mod = q % maxPos;
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q = (q - mod) / maxPos;
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uuid.push(chars[mod]);
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}
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return uuid.join('');
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}
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// 解析range
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export function parseRange(encoded: string | null): undefined | { offset: number, end: number, length: number } {
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if (encoded === null) {
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return
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}
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const parts = encoded.split("bytes=")[1]?.split("-") ?? []
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if (parts.length !== 2) {
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throw new Error('Not supported to skip specifying the beginning/ending byte at this time')
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}
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return {
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offset: Number(parts[0]),
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end: Number(parts[1]),
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length: Number(parts[1]) + 1 - Number(parts[0]),
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}
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}
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// 检查文件类是否支持
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export function checkFileType(val : string) : boolean {
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return supportFile.indexOf(val) > -1
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}
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// 获取文件名
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export async function getFileName(val : string, time : number) : Promise<string> {
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const types = supportFiles.filter(it => it.type === val)
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if (!types || types.length < 1) {
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return val
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}
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const rand = Math.floor(Math.random() * 100000)
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return randomString(time + rand).concat(`.${types[0].ext}`)
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}
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