React组件已被CORS策略阻止:请求的资源上不存在"Access-Control-Allow-Origin"标头 [英] React component has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource
问题描述
当我以前将其作为一个应用程序运行时,我使用fetch从我的react组件调用Web API,没有问题,但是当我运行该应用程序与API分开进行反应时,出现了CORS错误,我的提取呼叫如下所示,
I am calling the Web API from the my react component using fetch when I used to run it as one application, there was no problem, but when I am running the application react separate from API, I am getting the CORS error, my fetch call is as below,
componentDidMount() {
console.log(clientConfiguration)
fetch(clientConfiguration['communitiesApi.local'])
.then((response) => {
return response.json();
})
.then(data => {
console.log(data);
let communitiesFromApi = data.map(community => { return { value: community, display: community } });
this.setState({ communities: [{ value: '', display: 'Select a Community...' }].concat(communitiesFromApi) });
}).catch(error => {
console.log(error);
});
};
和我使用Axios的POST呼叫,如下所示.
and my POST call using Axios as below also.
handleDownload = (e) => {
e.preventDefault();
var formData = new FormData();
formData.append('communityname', this.state.selectedCommunity);
formData.append('files', JSON.stringify(this.state['checkedFiles']));
let url = clientConfiguration['filesApi.local'];
let tempFiles = clientConfiguration['tempFiles.local'];
axios({
method: 'post',
responseType: 'application/zip',
contentType: 'application/zip',
url: url,
data: formData
})
.then(res => {
var fileName = `${this.state['selectedCommunity']}.zip`;
saveAs(`https://localhost:44352/TempFiles/${res.data}`, fileName);
});
};
这是我的服务器端api代码:
Here is my server side api code:
[HttpGet("{communityName}")]
public string Get(string communityName)
{
string rootPath = Configuration.GetValue<string>("ROOT_PATH");
string communityPath = rootPath + "\\" + communityName;
string[] files = Directory.GetFiles(communityPath);
List<string> strippedFiles = new List<string>();
foreach (string file in files)
{
strippedFiles.Add(file.Replace(communityPath + "\\", ""));
}
return JsonConvert.SerializeObject(strippedFiles);
}
[HttpPost]
public string Post([FromForm] string communityName, [FromForm] string files) //FileContentResult
{
var removedInvalidCharsFromFileName = removeInvalidCharsFromFileName(files);
var tFiles = removedInvalidCharsFromFileName.Split(',');
string rootPath = Configuration.GetValue<string>("ROOT_PATH");
string communityPath = rootPath + "\\" + communityName;
byte[] theZipFile = null;
using (MemoryStream zipStream = new MemoryStream())
{
using (ZipArchive zip = new ZipArchive(zipStream, ZipArchiveMode.Create, true))
{
foreach (string attachment in tFiles)
{
var zipEntry = zip.CreateEntry(attachment);
using (FileStream fileStream = new FileStream(communityPath + "\\" + attachment, FileMode.Open))
using (Stream entryStream = zipEntry.Open())
{
fileStream.CopyTo(entryStream);
}
}
}
theZipFile = zipStream.ToArray();
}
////return File(theZipFile, "application/zip", communityName + ".zip");
string tempFilesPath = Configuration.GetValue<string>("Temp_Files_Path");
if (!System.IO.Directory.Exists(tempFilesPath))
System.IO.Directory.CreateDirectory(tempFilesPath);
System.IO.File.WriteAllBytes($"{tempFilesPath}\\{communityName}.zip", theZipFile);
//return System.IO.File.ReadAllBytes($"{tempFilesPath}\\Test.zip");
//return $"{tempFilesPath}\\{communityName}.zip";
return $"{communityName}.zip";
}
我得到了Get的错误,如下所示:访问在'
And I am getting the error for Get as below: "Access to fetch at 'https://localhost:44368/api/communities' from origin 'http://localhost:3000' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource. If an opaque response serves your needs, set the request's mode to 'no-cors' to fetch the resource with CORS disabled."
推荐答案
您需要修改服务器.您需要
You'll need to modify your sever. You'll need to
- 在服务器端启用CORS,并且
- 将您将在其中托管前端的域添加到允许的来源"列表中.
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