节点.JS将可变长度二进制数据转换为 jpeg 或 png

我想知道如何将Variable-length binary data（255216255224016747073700110010100255）转换为jpeg或png到Web浏览器？

示例代码：

var Connection = require('tedious').Connection;
    var config = {
        "userName": "user@server.database.windows.net",
        "password": "pswd",
        "server": "server.database.windows.net",
        "options": {
                "database": "db",
                "encrypt": true,
        }
    };
    var connection = new Connection(config);
    connection.on('connect', function(err) {
            console.log("Connected");
        }
    );
var Request = require('tedious').Request;
var result,
    resG;
    function sendResponse() {
        var vals;
            // Convert to string then array
        var resultA = result.toString().split(',');
            // Now I can loop through the data returned
        resultA.forEach(function(val, index, ar) {
            if(vals == null) {
                vals = val;
            } else {
                vals += val;
            }   
        });
        resG.writeHead(200, {'Content-Type': 'text/html', 'Content-Length': vals.length});
        //console.log(vals);
        //resG.end("<img src="data:image/jpg;base64," + vals + "" />");
            // Output data returned from db as string
        resG.end("" + vals);
    }
    function executeStatement() {
         request = new Request("SELECT Photos FROM dbo.tbl WHERE FarmerFirstName='someName' AND FarmerLastName='someLastName'", function(err, rowCount) {
                if (err) {
                    console.log(err);
                } else {
                    console.log(rowCount + ' rows');
                }
            });
            request.on('row', function(columns) {
                columns.forEach(function(column) {
                    result = column.value;
                });
            });
        request.on('doneInProc', function(rowCount, more) {
                    // Got everything needed from db move on to sending a response
            sendResponse();
        });
            connection.execSql(request);
    }
var http = require('http'),
    director = require('director');
var router = new director.http.Router({
    "/": {
        get: executeStatement
    }
});
var server = http.createServer(function (req, res) { 
  // set global res var
  resG = res;
  router.dispatch(req, res, function (err) {
    if (err) {
      res.writeHead(404);
      res.end();
    }
 });
});
server.listen(80);

我使用繁琐的数据库连接器和控制器作为我的路由器。

result已经是图像的字节数组。您无需对其进行任何花哨的转换。这应该有效。

function sendResponse() {
    resG.writeHead(200, {'Content-Type': 'image/jpeg', 'Content-Length': result.length});
    resG.end(new Buffer(result));
}

或者，如果您想将其作为 HTML 页面的一部分提供，请执行以下操作：

function sendResponse() {
    resG.writeHead(200, {'Content-Type': 'text/html'});
    var vals = (new Buffer(result)).toString('base64')
    resG.end("<html><body>" +
        "<img src="data:image/jpg;base64," + vals + "" />" +
        "</body></html>");
}

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