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| "use strict";
const AWS = require('aws-sdk');
const Storage = require('./Storage');
/**
* Use a AWS S3 bucket as storage.
*
* Requires ```aws-sdk``` package.
*/
class S3Storage extends Storage
{
/**
* @param {StorageOptions} options see fields
*/
constructor(options)
{
super(options)
/** AWS region */
this.region = options.region;
/** reference to driver object */
this.s3 = new AWS.S3({
apiVersion: '2006-03-01',
endpoint: this.connectionString,
region: this.region,
s3ForcePathStyle: true
});
}
/** @override */
connect()
{
return new Promise((resolve, reject) =>
{
this.listItems()
.then(list => resolve(this.list = list), reject);
});
}
/** s3 list gives us last modified date; use that to efficiently check for updates */
listItems()
{
const that = this;
return new Promise((resolve, reject) =>
{
let output = {};
function iterate(ContinuationToken)
{
that.s3.listObjectsV2({
Bucket: that.collectionName,
ContinuationToken
}, (err, data) =>
{
Iif (err)
{
return reject(err);
}
data.Contents.forEach(item =>
{
output[item.Key] = item.LastModified;
});
Eif (!data.IsTruncated)
{
resolve(output);
}
else
{
iterate(data.NextContinuationToken);
}
});
}
iterate();
});
}
/** @override */
readAllRecords()
{
return new Promise((resolve, reject) =>
{
Promise.all(Object.keys(this.list)
.map(item =>
{
let query = {};
query[this.primaryKey] = item;
return this.readRecord(query);
}))
.then(resolve, reject);
});
}
/** @override */
createRecord(record)
{
return this.updateRecord(record);
}
/** @override */
readRecord(record)
{
return new Promise((resolve, reject) =>
{
this.s3.getObject({
Bucket: this.collectionName,
Key: record[this.primaryKey]
}, (err, data) =>
{
if (err)
{
reject(err);
}
else
{
this.list[record[this.primaryKey]] = data.LastModified;
resolve(JSON.parse(data.Body));
}
});
});
}
/** @override */
updateRecord(record)
{
return new Promise((resolve, reject) =>
{
this.s3.upload({
Bucket: this.collectionName,
Key: record[this.primaryKey],
Body: JSON.stringify(record)
}, (err, data) =>
{
Iif (err)
{
reject(err);
}
else
{
resolve(this.readRecord(record));
}
});
});
}
/** @override */
deleteRecord(record)
{
return new Promise((resolve, reject) =>
{
this.s3.deleteObject({
Bucket: this.collectionName,
Key: record[this.primaryKey]
}, (err, data) =>
{
Iif (err)
{
reject(err);
}
else
{
resolve(record);
}
});
});
}
/** @override */
async updateCheckImpl()
{
let updated = false;
let newlist = await this.listItems();
let list = this.list,
record = {};
// check for deleted item
for (let item in list)
{
if (!newlist[item])
{
record[this.primaryKey] = item;
this.emit('delete', record);
delete list[item];
updated = true;
}
}
// check for new items
for (let item in newlist)
{
if (!list[item])
{
record[this.primaryKey] = item;
this.readRecord(Object.assign({}, record))
.then(record =>
{
this.emit('create', record);
updated = true;
}, x => x);
list[item] = newlist[item];
}
}
// check for modified items
for (let item in list)
{
if (list[item].getTime() !== newlist[item].getTime())
{
record[this.primaryKey] = item;
this.readRecord(Object.assign({}, record))
.then(record =>
{
this.emit('update', record);
updated = true;
}, x => x);
list[item] = newlist[item];
}
}
return updated;
}
}
module.exports = S3Storage;
|