s3-readstream
Version:
*Updated for AWS-SDK v3* Zero dependency S3Client streaming solution
152 lines • 7.39 kB
JavaScript
"use strict";
var __extends = (this && this.__extends) || (function () {
var extendStatics = function (d, b) {
extendStatics = Object.setPrototypeOf ||
({ __proto__: [] } instanceof Array && function (d, b) { d.__proto__ = b; }) ||
function (d, b) { for (var p in b) if (Object.prototype.hasOwnProperty.call(b, p)) d[p] = b[p]; };
return extendStatics(d, b);
};
return function (d, b) {
if (typeof b !== "function" && b !== null)
throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
extendStatics(d, b);
function __() { this.constructor = d; }
d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
};
})();
var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
return new (P || (P = Promise))(function (resolve, reject) {
function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
function step(result) { result.done ? resolve(result.value) : adopt(result.value).then(fulfilled, rejected); }
step((generator = generator.apply(thisArg, _arguments || [])).next());
});
};
var __generator = (this && this.__generator) || function (thisArg, body) {
var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
function verb(n) { return function (v) { return step([n, v]); }; }
function step(op) {
if (f) throw new TypeError("Generator is already executing.");
while (_) try {
if (f = 1, y && (t = op[0] & 2 ? y["return"] : op[0] ? y["throw"] || ((t = y["return"]) && t.call(y), 0) : y.next) && !(t = t.call(y, op[1])).done) return t;
if (y = 0, t) op = [op[0] & 2, t.value];
switch (op[0]) {
case 0: case 1: t = op; break;
case 4: _.label++; return { value: op[1], done: false };
case 5: _.label++; y = op[1]; op = [0]; continue;
case 7: op = _.ops.pop(); _.trys.pop(); continue;
default:
if (!(t = _.trys, t = t.length > 0 && t[t.length - 1]) && (op[0] === 6 || op[0] === 2)) { _ = 0; continue; }
if (op[0] === 3 && (!t || (op[1] > t[0] && op[1] < t[3]))) { _.label = op[1]; break; }
if (op[0] === 6 && _.label < t[1]) { _.label = t[1]; t = op; break; }
if (t && _.label < t[2]) { _.label = t[2]; _.ops.push(op); break; }
if (t[2]) _.ops.pop();
_.trys.pop(); continue;
}
op = body.call(thisArg, _);
} catch (e) { op = [6, e]; y = 0; } finally { f = t = 0; }
if (op[0] & 5) throw op[1]; return { value: op[0] ? op[1] : void 0, done: true };
}
};
Object.defineProperty(exports, "__esModule", { value: true });
exports.S3ReadStream = void 0;
var stream_1 = require("stream");
var S3ReadStream = /** @class */ (function (_super) {
__extends(S3ReadStream, _super);
function S3ReadStream(options, nodeReadableStreamOptions) {
var _this = _super.call(this, nodeReadableStreamOptions) || this;
_this._currentCursorPosition = 0;
_this._maxContentLength = options.maxLength;
_this._s3 = options.s3;
_this._command = options.command;
_this._s3DataRange = options.byteRange || 64 * 1024;
return _this;
}
S3ReadStream.prototype.drainBuffer = function () {
while (this.read())
;
};
/**
* Adjust size of range to grab from S3
*
* @param {number} bytes - Number of bytes to set for range
*/
S3ReadStream.prototype.adjustByteRange = function (bytes) {
this._s3DataRange = bytes;
};
/**
* Drains the internal buffer and
* moves cursor bytes length back in file
*
* If current cursor position - number of bytes to move back
* is <= 0, set cursor at begining of file
* @param {number} bytes - Number of bytes to subtract from cursor (defaults to range)
*/
S3ReadStream.prototype.moveCursorBack = function (bytes) {
if (bytes === void 0) { bytes = this._s3DataRange; }
this.drainBuffer();
if (this._currentCursorPosition - bytes > 0) {
this._currentCursorPosition -= bytes;
}
else {
this._currentCursorPosition = 0;
}
};
/**
* Drains the internal buffer and
* moves cursor bytes length forward in file
*
* If current cursor position + number of bytes to move forward
* is > the length of the file, set cursor at end of file
* @param {number} bytes - Number of bytes to add to cursor (defaults to range)
*/
S3ReadStream.prototype.moveCursorForward = function (bytes) {
if (bytes === void 0) { bytes = this._s3DataRange; }
this.drainBuffer();
if (this._currentCursorPosition + bytes <= this._maxContentLength) {
this._currentCursorPosition += bytes;
}
else {
this._currentCursorPosition += this._maxContentLength + 1;
}
};
S3ReadStream.prototype._read = function () {
return __awaiter(this, void 0, void 0, function () {
var range, adjustedRange, response, data, error_1;
return __generator(this, function (_a) {
switch (_a.label) {
case 0:
if (!(this._currentCursorPosition >= this._maxContentLength)) return [3 /*break*/, 1];
this.push(null);
return [3 /*break*/, 6];
case 1:
range = this._currentCursorPosition + this._s3DataRange;
adjustedRange = range < this._maxContentLength ? range : this._maxContentLength;
this._command.input.Range = "bytes=".concat(this._currentCursorPosition, "-").concat(adjustedRange);
this._currentCursorPosition = adjustedRange + 1;
_a.label = 2;
case 2:
_a.trys.push([2, 5, , 6]);
return [4 /*yield*/, this._s3.send(this._command)];
case 3:
response = _a.sent();
return [4 /*yield*/, response.Body.transformToByteArray()];
case 4:
data = _a.sent();
this.push(data);
return [3 /*break*/, 6];
case 5:
error_1 = _a.sent();
this.destroy(error_1);
return [3 /*break*/, 6];
case 6: return [2 /*return*/];
}
});
});
};
return S3ReadStream;
}(stream_1.Readable));
exports.S3ReadStream = S3ReadStream;
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