计算Google Firestore文件的大小 [英] Calculating size of Google Firestore documents

问题描述

Firestore文档提供了有关如何手动计算文档的存储大小的详细信息，但是在文档参考，快照或元数据中，似乎都没有为此提供任何功能.

Firestore docs give details of how to manually calculate the stored size of a document, but there does not seem to be a function provided for this on any of document reference, snapshot, or metadata.

在我尝试使用自己的计算方式之前，是否有人知道用于此目的的官方或非官方职能?

Before I attempt to use my own calculation, does anyone know of an official or unofficial function for this?

根据我对文档的解释，这是我(完全未经测试)的第一个切入点，位于

Here is my (completely untested) first cut for such a function from my interpretation of the docs at https://firebase.google.com/docs/firestore/storage-size

function calcFirestoreDocSize(collectionName, docId, docObject) {
    let docNameSize = encodedLength(collectionName) + 1 + 16
    let docIdType = typeof(docId)
    if(docIdType === 'string') {
        docNameSize += encodedLength(docId) + 1
    } else {
        docNameSize += 8
    }  
    let docSize = docNameSize + calcObjSize(docObject)

    return  docSize
}
function encodedLength(str) {
    var len = str.length;
    for (let i = str.length - 1; i >= 0; i--) {
        var code = str.charCodeAt(i);
        if (code > 0x7f && code <= 0x7ff) {
            len++;
        } else if (code > 0x7ff && code <= 0xffff) {
            len += 2;
        } if (code >= 0xDC00 && code <= 0xDFFF) {
            i--;
        }
    }
    return len;
}

function calcObjSize(obj) {
    let key;
    let size = 0;
    let type = typeof obj;

    if(!obj) {
        return 1
    } else if(type === 'number') {
        return 8
    } else if(type === 'string') {
        return encodedLength(obj) + 1
    } else if(type === 'boolean') {
        return 1
    } else if (obj instanceof Date) {
        return 8
    } else if(obj instanceof Array) {
        for(let i = 0; i < obj.length; i++) {
            size += calcObjSize(obj[i])
        }
        return size
    } else if(type === 'object') {

        for(key of Object.keys(obj)) {
            size += encodedLength(key) + 1 
            size += calcObjSize(obj[key])
        }
        return size += 32
    }
}

推荐答案

在Android中，如果您要针对最大1 MiB(1,048,576字节)的大小检查文档的大小，则可以使用一个库来帮助您

In Android, if you want to check the size of a document against the maximum of 1 MiB (1,048,576 bytes), there is a library that can help you with that:

• https://github.com/alexmamo/FirestoreDocument-Android/tree/master/firestore-document

通过这种方式，您将始终可以保持在限制之下.该库背后的算法是官方文档中针对存储大小.

In this way, you'll be able to always stay below the limit. The algorithm behind this library is the one that is explained in the official documentation regarding the Storage Size.

这篇关于计算Google Firestore文件的大小的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！