使用Alamofire和PHP实现iOS应用图片上传：完整指南与常见问题解决

import UIKit
import Alamofire

// 假设您已经有一个UIImage对象，例如从相册或相机获取
let myImage: UIImage? = UIImage(named: "example_image") // 或者从其他来源获取

guard let imageToUpload = myImage,
      let imageData = imageToUpload.pngData() else {
    print("图片数据无效或无法转换为PNG格式")
    return
}

let uploadURL = URL(string: "YOUR_PHP_UPLOAD_URL_HERE")! // 替换为您的PHP上传接口URL

AF.upload(
    multipartFormData: { multipartFormData in
        // 将图片数据添加到表单中
        // "image" 必须与PHP端 $_FILES["image"] 的键名匹配
        multipartFormData.append(imageData, withName: "image", fileName: "test.png", mimeType: "image/png")

        // 如果需要，还可以添加其他文本参数
        // multipartFormData.append("some_value".data(using: .utf8)!, withName: "some_key")

        print("准备上传图片...")
    },
    to: uploadURL,
    method: .post // 明确指定POST方法
)
.uploadProgress { progress in
    // 可以在这里更新上传进度UI
    print("上传进度: \(progress.fractionCompleted * 100)%")
}
.responseJSON { response in
    // 处理服务器响应
    switch response.result {
    case .success(let json):
        print("上传成功，服务器响应: \(json)")
    case .failure(let error):
        print("上传失败，错误: \(error)")
        if let data = response.data, let errorString = String(data: data, encoding: .utf8) {
            print("服务器原始错误数据: \(errorString)")
        }
    }
}

<?php

header('Content-Type: application/json'); // 确保响应是JSON格式

$response = array();

// 检查是否存在名为 "image" 的文件上传
if (empty($_FILES["image"])) {
    $response["error"] = "nodata"; // 没有接收到文件数据
    $response["message"] = "No file uploaded with name 'image'.";
} else {
    // 检查上传过程中是否有错误
    if ($_FILES["image"]["error"] !== UPLOAD_ERR_OK) {
        $response["status"] = "Failure";
        $response["error_code"] = $_FILES["image"]["error"];
        $response["message"] = "Upload error occurred. Error code: " . $_FILES["image"]["error"];
        // 详细错误码解释：
        // UPLOAD_ERR_INI_SIZE (1): 上传文件大小超出php.ini中upload_max_filesize限制
        // UPLOAD_ERR_FORM_SIZE (2): 上传文件大小超出HTML表单中MAX_FILE_SIZE限制
        // UPLOAD_ERR_PARTIAL (3): 文件只有部分被上传
        // UPLOAD_ERR_NO_FILE (4): 没有文件被上传
        // UPLOAD_ERR_NO_TMP_DIR (6): 找不到临时文件夹
        // UPLOAD_ERR_CANT_WRITE (7): 文件写入失败
        // UPLOAD_ERR_EXTENSION (8): PHP扩展阻止了文件上传
    } else {
        // 获取文件信息
        $filename = $_FILES["image"]["name"];
        $tempFilePath = $_FILES["image"]["tmp_name"];
        $fileType = $_FILES["image"]["type"];
        $fileSize = $_FILES["image"]["size"];

        // 定义目标保存路径
        // 注意：在Windows系统上使用D:/emailback/images/，Linux/macOS上使用/var/www/html/images/等
        // 确保目标目录存在且PHP进程有写入权限
        $uploadDir = "D:/emailback/images/"; // 请替换为您的实际上传目录

        // 检查上传目录是否存在，不存在则尝试创建
        if (!is_dir($uploadDir)) {
            mkdir($uploadDir, 0777, true); // 0777表示最高权限，生产环境请根据需要调整
        }

        $targetPath = $uploadDir . $filename;

        // 将临时文件移动到目标目录
        if (move_uploaded_file($tempFilePath, $targetPath)) {
            $response["status"] = "success";
            $response["message"] = "File uploaded successfully.";
            $response["filename"] = $filename;
            $response["filepath"] = $targetPath;
            $response["filetype"] = $fileType;
            $response["filesize"] = $fileSize;
        } else {
            $response["status"] = "Failure";
            $response["message"] = "Failed to move uploaded file.";
            $response["error_info"] = error_get_last(); // 获取最近的错误信息
            $response["filename"] = $filename;
            $response["filepath"] = $targetPath;
            $response["filetype"] = $fileType;
            $response["filesize"] = $fileSize;
        }
    }
}

echo json_encode($response);

?>