javascript - 使用输入数据减去文件类型创建新的 formData

Question

我需要根据用户输入(从 html 表单发送)创建一个 formData，因为我需要修改图像图片(压缩/调整大小/裁剪)，然后将新的 FormData 提交到服务器:

    $(document).ready(function () {

        $("#AddModel").on("submit", function (e) {

            e.preventDefault();

            var formData    = new FormData(this);
            var formKeys    = formData.keys();
            var formEntries = formData.entries();

            var processedForm = new FormData();

            // some loop to insert in processedForm all the entries
            // less the file type

            // get the file type (image), process it with canvas and append
            // to the processedForm

            //submit the form

            $.ajax({
            type: 'POST',
            url: form.prop('action'),
            processData: false,
            contentType: false,
            data: processedForm,
            success: function (data) {

                console.log(data)

            },

        });
    });

我知道如何修改图像，然后附加到processedForm，但是如何创建processedForm获取用户输入并将每个输入附加到其中，但文件除外？我在 formKeys 上尝试了一些 if，例如 if (formKeys != 'image') 但无济于事，因为它似乎无法识别该 key (console.log(formKeys) )仅返回一些输入而不是图像。那么这个循环如何工作呢？

-- 到目前为止尝试实现 @Kaiido 方法的进展:

结果是:无法处理的实体:{image: ["图像字段为必填项。"]}

当然我的 Controller 中有这个:

'image' => 'required|mimes:jpeg,jpg,png,gif|image|image_size:>=640'

我有所有这些代码，它们返回一个带有修改后的图像的 Blob ，并理论上将其附加到表单中，但是 Controller 认为图像不存在:

$(document).ready(function () {

    $("#AddModel").on("submit", function (e) {
        e.preventDefault();

        var form = $(this);

        var inputs = $(this).find('[name]'),

            formData = new FormData();


        inputs.each(function (index, element) {
            if (element.type === 'file') {

                var file = element.files[0];


                if (file.type.match('image.*')) {

                    console.log("it's an image");

                }

                var reader = new FileReader();

                reader.readAsDataURL(file);

                reader.onloadend = function () {

                    var base64img = this.result;

                    var exif = EXIF.readFromBinaryFile(base64ToArrayBuffer(this.result));
                    var srcOrientation = exif.Orientation;

                    resetOrientationResizeCompress(base64img, srcOrientation).then((img)=> {

                        console.log(img);

                        dataURItoBlob(img).then((ia)=> {

                            console.log(ia);

                            console.log(element.name);

                            formData.append(element.name, ia);

                        });

                    });

                }


            } else {

                formData.append(element.name, element.value);
            }

        });


        $.ajax({
            type: 'POST',
            url: form.prop('action'),
            processData: false,
            contentType: false,
            data: formData,
            success: function (data) {

                console.log(data)

            }
        });
    });

//该函数处理原始图像

function resetOrientationResizeCompress(srcBase64, srcOrientation) {
    return new Promise(function (resolve) {

        var img = new Image();

        img.onload = function () {
            var width = img.width,
                height = img.height,
                canvas = document.createElement('canvas'),
                ctx = canvas.getContext("2d");

            var MAX_WIDTH = 1000;
            var MAX_HEIGHT = 1000;

            // set proper canvas dimensions before transform & export
            if ([5, 6, 7, 8].indexOf(srcOrientation) > -1) {
                if (width > height) {
                    if (width > MAX_WIDTH) {
                        height *= MAX_WIDTH / width;
                        width = MAX_WIDTH;
                    }
                } else {
                    if (height > MAX_HEIGHT) {
                        width *= MAX_HEIGHT / height;
                        height = MAX_HEIGHT;
                    }
                }
                canvas.width = height;
                canvas.height = width;
            } else {
                if (height > MAX_HEIGHT) {
                    width *= MAX_HEIGHT / height;
                    height = MAX_HEIGHT;
                }
                canvas.width = width;
                canvas.height = height;
            }

            // transform context before drawing image
            switch (srcOrientation) {
                case 2:
                    ctx.transform(-1, 0, 0, 1, width, 0);
                    break;
                case 3:
                    ctx.transform(-1, 0, 0, -1, width, height);
                    break;
                case 4:
                    ctx.transform(1, 0, 0, -1, 0, height);
                    break;
                case 5:
                    ctx.transform(0, 1, 1, 0, 0, 0);
                    break;
                case 6:
                    ctx.transform(0, 1, -1, 0, height, 0);
                    break;
                case 7:
                    ctx.transform(0, -1, -1, 0, height, width);
                    break;
                case 8:
                    ctx.transform(0, -1, 1, 0, 0, width);
                    break;
                default:
                    ctx.transform(1, 0, 0, 1, 0, 0);
            }

            // draw image
            ctx.drawImage(img, 0, 0, width, height);

            // export base64
            resolve(canvas.toDataURL("image/jpeg", 0.6));
        };

        img.src = srcBase64;

    })

};

//这个将base64转换为数组缓冲区

   function base64ToArrayBuffer(base64) {

        //base64 = base64.replace(/^data\:([^\;]+)\;base64,/gmi, '');
        base64 = base64.replace(/^data:([^;]+);base64,/gmi, '');
        var binaryString = window.atob(base64);
        var len = binaryString.length;
        var bytes = new Uint8Array(len);
        for (var i = 0; i < len; i++) {
            bytes[i] = binaryString.charCodeAt(i);
        }
        return bytes.buffer;
    }

//这个将 dataURItoBlob 转换(也许我可以直接转换 canvas.toBlob() 但我没有在该方法中获得回调参数。

 function dataURItoBlob(dataURI) {

        return new Promise(function (resolve) {

            // convert base64/URLEncoded data component to raw binary data held in a string
            var byteString;
            if (dataURI.split(',')[0].indexOf('base64') >= 0)
                byteString = atob(dataURI.split(',')[1]);
            else
                byteString = unescape(dataURI.split(',')[1]);

            // separate out the mime component
            var mimeString = dataURI.split(',')[0].split(':')[1].split(';')[0];

            // write the bytes of the string to a typed array
            var ia = new Uint8Array(byteString.length);
            for (var i = 0; i < byteString.length; i++) {
                ia[i] = byteString.charCodeAt(i);
            }

            resolve(new Blob([ia], {type: mimeString}));

        });
    }
});

Answer 1

您可以获取原始的formdata对象，然后为文件输入设置一个新值，添加更改后的图像等。

您还可以使用formData.delete()删除图像，然后将图像设置为新值

$("#AddModel").on("submit", function(e) {

  e.preventDefault();

  var formData = new FormData(this);
  var image = $('[name=image_input]').get(0).files[0]; // etc

  // change image here

  formData.set('image_input', changed_image_file);

  $.ajax({
    type: 'POST',
    url: form.prop('action'),
    processData: false,
    contentType: false,
    data: formData,
    success: function(data) {

      console.log(data)

    },

  });
});

如果浏览器支持是一个问题，您可以手动迭代表单输入并将它们附加到 formData 对象

$("#AddModel").on("submit", function(e) {
  e.preventDefault();

  var inputs   = $(this).find('[name]'),
      formData = new FormData();

  inputs.each(function(index, element) {
      if ( element.type === 'file' ) {
          var file = element.files[0];
          var changed_file = change(file);

          formData.append(element.name, changed_file);

      } else {
          formData.append(element.name, element.value);
      }

  });

  $.ajax({
    type: 'POST',
    url: form.prop('action'),
    processData: false,
    contentType: false,
    data: formData,
    success: function(data) {

      console.log(data)

    }
  });
});