blob | 易学教程

Creating Javascript Blob() with data from HTML Element. Then downloading it as a text file

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问题 I'm using an HTML5 site to create a log per-say within a textarea element. I need to pull the data from that area with the click of a button, and download it to my computer via a .txt file. How would I go about doing this if it is possible?? HTML: <input type="button" onclick="newBlob()" value="Clear and Export"> Javascript: function newBlob() { var blobData = document.getElementById("ticketlog").value; var myBlob = new Blob(blobData, "plain/text"); blobURL = URL.createObjectURL(myBlob); var

Reading of a file from Google Cloud Storage fails in a python + flask + gunicorn + nginx + Compute Engine app

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问题 Reading of a file downloaded from Google Cloud Storage fails in a python + flask + gunicorn + nginx + Compute Engine app. Link to the code: https://github.com/samuq/CE-test . The line number 64 of the file 'ETL_SHP_READ_SQL_WRITE' returns nothing, although the file is valid and has data in it: prj_blob.download_to_file(self.prj_file) logger.log_text(self.prj_file) line 64 --> euref_fin.ImportFromWkt(self.prj_file.read())). 回答1: file.seek(0) helped to solve the problem; somehow I assume that

Azure Function - writing and reading a blob file

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问题 This is my first post, pleas excuse me if i have made an errors. I am very new to Azure. I have created a function that is triggered by ASA using Service bus Queue. My data is passed into the function. I would like to know how i can create a blob file , the file name must be specific to a certain string. I would then like to write to the file or even read from the file. Are there any samples of writing and reading to files using Azure functions? I am correct i must use a binding process.

Can a Linq query retrieve BLOBs from a Sql Database?

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问题 Can a Linq query retrieve BLOBs from a Sql Database? And how do they come out? 回答1: LINQ-To-SQL classes create properties of type System.Data.Linq.Binary for all binary and varbinary fields in SQL-Server. The Binary type has a .ToArray() method that returns a byte[], and its constructor can take a byte[]. Older versions of SQLMetal generated properties of type byte[], but the problem with these was that they failed in any joins. I think that's the main reason they replaced it with the

Saving Blob as xlsx in Angular2

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问题 I have some issues with saving xlsx in my Angular2 app: this._http.get('/api/file).subscribe(success=>{ var blob = new Blob([success.json()], { type: 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet' }); var downloadUrl= window.URL.createObjectURL(blob); window.open(downloadUrl); }, error=>{ }); The response I receive from backend is in the following form: PK�q�H_rels/.rels��j�0��} �{㴃1F�^Ơ�2��l%1I,c�[��3�l l��H��4��R�l��·��q}*�2��;�*�� t"�^�l;1W)�N�iD)ejuD�cKz[׷:

Using JavaScript to inflate a blob?

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问题 I'm using a websocket to send a Jpeg image in blob form. I've compressed (gzipped) the blob but I'm unable to find a way to decompress it using JavaScript. Does anyone know how? This is the code I'm using to read the blob and then convert it into a base64 string: var r = new FileReader(); r.onload = function(){ draw(btoa(r.result)); }; r.readAsBinaryString(e.data); The draw() function basically draws the image using the base64 string, onto a HTML5 canvas. I've found this library to inflate

Blob 下载

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在这里插入代码片 // 点击下载 download = ( ) = > { const { table_Data } = this . props const blob = new Blob ( [ JSON . stringify ( table_Data ) ] , { type : 'text/plain' } ) // {type : 'application/json'} let a = document . createElement ( 'a' ) let url = URL . createObjectURL ( blob ) a . href = url a . download = '表格数据' a . click ( ) setTimeout ( ( ) = > { //删除创建的URL window . URL . revokeObjectURL ( url ) } , 0 ) } // 相关链接 // 【官方链接】 https://developer.mozilla.org/zh-CN/docs/Web/API/Blob // 【HTML5】Blob对象 https://www.jianshu.com/p/e45522c7f6c9 // URL.createObjectURL和URL.revokeObjectURL https://www.jianshu

Handling of huge Blobs in MySQL?

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问题 How can I insert huge BLOBs into a MySQL database (InnoDB)? Fields of type LONGBLOB support data sizes of up to 4 GB according to the MySQL manual. But how does data of such a huge size get into the database? I tried to use INSERT INTO table (bindata) VALUES ( LOAD_FILE('c:/tmp/hugefile') ); which fails if the size of hugefile is bigger than about 500 MB. I have set max_allowed_packet to an appropriate size; the value of innodb_buffer_pool_size doesn't seem to have an influence. My server

How to get correct SHA1 hash of BLOB using CryptoJS?

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问题 CryptoJS v3.1.2, sha1.js rollup In JS I want to calculate the SHA1 of a blob before sending it to the server. On the server I want to calculate the SHA1 of the resulting file and compare it to the SHA1 received from JS. The problem is that the hash generated by CryptoJS.SHA1() is incorrect (always 9844f81e1408f6ecb932137d33bed7cfdcf518a3) JS Code: function uploadFileslice (slice) { // slice is a blob var fileReader = new FileReader() fileReader.onload = function(event){ var arrayBuffer =

Oracle BLOB vs VARCHAR

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问题 I need to store a (large) SQL query in a column of a table and I thought using a BLOB field. To be clear, I want to store the query, not its result. What's best to use: BLOB or a VARCHAR ? Or something else maybe? 回答1: If you're going to store text data that can't fit in a VarChar2 then I think you're supposed to use a CLOB . Quote from OraFaq: *A CLOB (Character Large Object) is an Oracle data type that can hold up to 4 GB of data. CLOB's are handy for storing text. * 回答2: Another option is