我需要一个适合我问题的解决方案。所以我希望你们可以帮助我。 这是我的问题。我正在使用node.js graphicmagic工作lambda aws。 在我的aws S3文件夹中，我有一个16000x8000 jpg图像。 当我从s3下载图像是好的，然后调整大小并裁剪为512x512大小的瓷砖是好的。 但是当我通过toBuffer命令将所有生成的tile保存回S3时，它会导致Error：Stream产生空缓冲区。
这是我写的代码。
var clone = require('clone');
var fs = require('fs');
var os = require('os');
var async = require("async");
var gm = require("gm").subClass({imageMagick: true});
// require('gm-buffer');
var AWS = require("aws-sdk");
var s3 = new AWS.S3();
exports.handler = function(event, context) {
var bucketPath = event.bucketPath;
var baseDestinationPath = event.baseDestinationPath; // lambda/
// var bufferedImagePath = event.bufferedImagePath; // lambda/JFEmYgjxt4sG-equirectangular_16384.jpg
var bufferedImagePath = event.bufferedImagePathSmall; // lambda/
var bestResolutionLevel = 4;
var minIndex = 2;
var resolutions =[416, 832, 1664, 3328, 6656];
var tileSize = 512;
var _level2 = {
index: 2,
width: 1664,
height: 832,
destinationPath: baseDestinationPath +"level-" + 2
};
var _level3 = {
index: 3,
width: 3328,
height: 1664,
destinationPath: baseDestinationPath + "level-" + 3
};
var _level4 = {
index: 4,
width: 6656,
height: 3328,
destinationPath: baseDestinationPath + "level-" + 4
};
var _sizesArray = [];
s3.getObject({
Bucket: bucketPath,
Key: bufferedImagePath
}, function(err, data) {
if (err) { context.fail(err); }
gm(data.Body).size(function(err, size) {
if (err) { context.fail(err); }
var full_width = size.width;
var full_height = size.height;
if( full_width < resolutions[2])
{
context.fail('{"errorMessage": "Small Image", "errorType": "small", "successCode": 0}');
}
else
{
for(var index = 4; index >= 0; index--) // get best resolution levels
{
if(full_width >= resolutions[index])
{
bestResolutionLevel = index;
break;
}
} // end best resolution levels
for(var index = 2; index <= bestResolutionLevel; index++ )
{
var layer_width = 0, layer_height = 0;
if( index == bestResolutionLevel ) // check this is max resolution
{
if( bestResolutionLevel >= 4 ) // orignal image resolution (create max resolution image)
{
layer_width = resolutions[index];
layer_height = resolutions[index] / 2;
}
else
{
layer_width = full_width;
layer_height = full_height;
}
}
else
{
layer_width = resolutions[index];
layer_height = resolutions[index] / 2;
} // end check max resolution
switch(index) {
case 2: {
_level2.width = layer_width;
_level2.height = layer_height;
_sizesArray.push(_level2);
break;
}
case 3: {
_level3.width = layer_width;
_level3.height = layer_height;
_sizesArray.push(_level3);
break;
}
case 4: {
_level4.width = layer_width;
_level4.height = layer_height;
_sizesArray.push(_level4);
break;
}
}
} // End resulation sizes created
// Problem code is here
async.forEachOf(_sizesArray, function(value, key, callback) {
async.waterfall([
function download(next) {
s3.getObject({
Bucket: bucketPath,
Key: bufferedImagePath
}, next);
},
function convert(data, next) {
var gm_object = gm(data.Body).setFormat('JPEG');
next(null, gm_object);
},
function resizer(object, next) {
var width = _sizesArray[key].width;
var height = _sizesArray[key].height;
var gm_object = object.resize(width, height);
next(null, gm_object);
},
function croper(object, next) {
var response = null;
var x = 0, y = 0;
var width = _sizesArray[key].width;
var height = _sizesArray[key].height;
calcCropY(x, y);
function calcCropY(x, y) {
if( y < (height/tileSize) ) {
calcCropX(x, y);
}
else {
// END CROP
next(null);
}
}
function calcCropX(x, y) {
if( x < (width/tileSize) ) {
// do something
var position_x = x * tileSize;
var position_y = y * tileSize;
var clonedObject = clone(object);
var gm_object = clonedObject.crop(tileSize, tileSize, position_x, position_y);
// This code is big problem !!!!!!!!!!!!!!!!!!!!!!!!!!!!!
gm_object.toBuffer(function(err, buffer) {
if (err) { next(err); }
else {
s3.putObject({
Bucket: bucketPath,
Key: _sizesArray[key].destinationPath + "/X" + x + "Y" + y + ".jpg",
Body: buffer,
ContentType: 'JPG'
}, function(err) {
x ++;
calcCropY(x, y);
});
}
});
}
else {
x = 0;
y ++;
calcCropY(x, y);
}
}
}
], function(err, result) {
if (err) { console.error(err); }
callback();
});
}, function(err) {
if (err)
{
console.error(err);
context.fail(err);
}
else
{
console.log("Successfully done!");
context.done();
}
}); // End image processing
}
});
});
};
任何帮助都会很感激。