ASP. NET Core Learning Notes (upload/download files file upload and download)

2017-09-25

Refer:https://docs.microsoft.com/en-us/aspnet/core/mvc/models/file-uploads

Https://www.codeproject.com/Articles/1203408/Upload-Download-Files-in-ASP-NET-Core

This is just about small file uploads.

First look at the front-end JS code

<inputID= "Inputfile"type= "File" /><Script>document.getElementById ('Inputfile'). AddEventListener (' Change', (e)={Let files=E.target.files; Let FormData= NewFormData (); Formdata.append ("file", files[0]); Let HTTP= NewXMLHttpRequest (); Http.open ('POST', '/upload-file', true);     Http.send (FormData); }, false); </Script>

If you want to upload multiple files, just append a few more.

C#

 Public classuploadfiledata{ PublicIformfile file {Get;Set; }} [Area ("Web")] Public classuploadcontroller:controller{ PublicUploadcontroller (ihostingenvironment environment) { This. Environment =environment; }    PrivateIhostingenvironment Environment {Get;Set; } [HttpPost ("Upload-file")]     Public AsyncTask<iactionresult>uploadfile (uploadfiledata data) {varAllfiles = Request.Form.Files;//multiple files can be obtained directly from the form.        varRoot =environment.        Webrootpath; varExtension =path.getextension (data.file.FileName); varGUID =Guid.NewGuid ().        ToString (); varFullPath = $@"{root}\images\{guid + extension}"; using(FileStream stream =NewFileStream (FullPath, FileMode.Create)) {            awaitData.file.CopyToAsync (stream); }         returnOk (); } [Route ("Upload")]     Public AsyncTask<iactionresult>Index () {returnView (); }}

Above is the simplest version, create file and then write the upload file stream

There is also a common scenario is that uploading images to do EXIF processing.

The core can now be supported with magick.net, but it seems to support only the window scene. If you are not windows you may want to wait or use a different plugin.

using(varstream =Data.file.OpenReadStream ())using(Magickimage image =NewMagickimage (Stream)) {Exifprofile profile=image.    Getexifprofile (); Image. Settings.setdefine (Magickformat.jpeg,"Sampling-factor","4:2:0"); Image. Strip (); //This will wash out all the EXIF images.Image. Quality = -; if(Profile! =NULL) {Exifvalue orientation= Profile. Values.singleordefault (v = V.tag = =exiftag.orientation); if(Orientation! =NULL)        {            intOrientationint =Convert.ToInt32 (orientation.            Value); if(Orientationint = =6) {image. Rotate ( -); }            Else if(Orientationint = =8) {image. Rotate (- -); }            Else if(Orientationint = =8) {image. Rotate ( the); }} image.    Write (FullPath); }    Else{image.    Write (FullPath); }}

It's simple.

One more zip.

using(varstream =Data.file.OpenReadStream ())using(varCompressedfilestream =NewFileStream ($@"{root}\images\{guid}.zip", FileMode.Create))using(varZiparchive =NewZiparchive (Compressedfilestream, Ziparchivemode.update,false)){    varZipEntry =ziparchive.createentry (data.file.FileName); using(varZipentrystream =Zipentry.open ()) {stream.    CopyTo (Zipentrystream); }}

Core Support Ziparchive OH

Download is also easy

 PublicUploadcontroller (ihostingenvironment environment, Icontenttypeprovider Contenttypeprovider) { This. Environment =environment;  This. Contenttypeprovider =Contenttypeprovider;}PrivateIhostingenvironment Environment {Get;Set; }PrivateIcontenttypeprovider Contenttypeprovider {Get;Set; } [HttpGet ("Download-file")] PublicFileresult DownloadFile (stringNamestringdisplay) {    stringContentType; Contenttypeprovider.trygetcontenttype (Name, outContentType); HttpContext.Response.ContentType=ContentType; stringPath = environment. Webrootpath +@"\images\"+ Name;//Note Oh, do not use the client's value directly as me to stitch the path, dangerousFilecontentresult result =NewFilecontentresult (System.IO.File.ReadAllBytes (path), ContentType) {filedownloadname=display}; returnresult;}

Html

<href= "/download-file?name=123.jpg&display=aaa.jpg"  download   >download</a>

ASP. NET Core Learning Notes (upload/download files file upload and download)