问题

业务场景上存在需要将手机里的文件、图片传递给其他的设备，

不仅仅局限于传书、资料啥的都有可能传递

方案

最base的方法：设备之间加个云，设备上传资料到云，云同步资料到各个设备，适用于多设备之间，这个没讲的必要

如果是两设备之间，忽略服务器，怎么搞？联想到图书App中的WiFi传书，貌似没云端概念的，怎么做到的？

上菜

• 采用框架GCDWebServer，通过CocoaPods引入

pod "GCDWebServer", "~> 3.0"

• 设置本地接收目录，初始化Server并启动

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)
    
    if let filepath = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true).first as NSString? {
        let path = filepath.appendingPathComponent("transfer")
        if !FileManager.default.fileExists(atPath: path) {
            do {
                try FileManager.default.createDirectory(atPath: path, withIntermediateDirectories: false, attributes: nil)
            } catch {
                print(error)
            }
        }
        
        webServer = GCDWebUploader(uploadDirectory: path)
        webServer?.delegate = self
        webServer?.allowHiddenItems = true
        webServer?.allowedFileExtensions = ["doc", "docx", "xls", "xlsx", "txt", "pdf", "jpeg", "jpg"]
        webServer?.title = "善斋工具"
        webServer?.prologue = "欢饮使用善斋工具的WIFI管理平台"
        webServer?.epilogue = "善斋书屋制作"
        
        if webServer?.start() == true, let address = IPHelper.deviceIPAdress(), address.count > 0, let port = webServer?.port {
            ipLb.text = "1.确保设备在同一局域网 \n2.上传时勿关闭该页面 \n3.请网页中输入该地址 \nhttp://\(address):\(port)/"
        } else {
            ipLb.text = "GCDWebServer not running!"
        }
    }
}

• 局域网内获取本机的ip地址，并设置其他设备访问链接

#import <ifaddrs.h>
#import <arpa/inet.h>
#import <net/if.h>

@implementation IPHelper

+ (NSString *)deviceIPAdress {
    NSString *address = @"";
    struct ifaddrs *interfaces = NULL;
    struct ifaddrs *temp_addr = NULL;
    int success = 0;
    success = getifaddrs(&interfaces);
    if (success == 0) { // 0 表示获取成功
        temp_addr = interfaces;
        while (temp_addr != NULL) {
            if( temp_addr->ifa_addr->sa_family == AF_INET) {
                // Check if interface is en0 which is the wifi connection on the iPhone
                if ([[NSString stringWithUTF8String:temp_addr->ifa_name] isEqualToString:@"en0"]) {
                    // Get NSString from C String
                    address = [NSString stringWithUTF8String:inet_ntoa(((struct sockaddr_in *)temp_addr->ifa_addr)->sin_addr)];
                }
            }
            temp_addr = temp_addr->ifa_next;
        }
    }
    freeifaddrs(interfaces);
    return address;
    
}


#define IOS_CELLULAR    @"pdp_ip0"
#define IOS_WIFI        @"en0"
#define IOS_VPN         @"utun0"
#define IP_ADDR_IPv4    @"ipv4"
#define IP_ADDR_IPv6    @"ipv6"

#pragma mark - 获取设备当前网络IP地址
+ (NSString *)getIPAddress:(BOOL)preferIPv4 {
    NSArray *searchArray = preferIPv4 ?
    @[ IOS_VPN @"/" IP_ADDR_IPv4, IOS_VPN @"/" IP_ADDR_IPv6, IOS_WIFI @"/" IP_ADDR_IPv4, IOS_WIFI @"/" IP_ADDR_IPv6, IOS_CELLULAR @"/" IP_ADDR_IPv4, IOS_CELLULAR @"/" IP_ADDR_IPv6 ] :
    @[ IOS_VPN @"/" IP_ADDR_IPv6, IOS_VPN @"/" IP_ADDR_IPv4, IOS_WIFI @"/" IP_ADDR_IPv6, IOS_WIFI @"/" IP_ADDR_IPv4, IOS_CELLULAR @"/" IP_ADDR_IPv6, IOS_CELLULAR @"/" IP_ADDR_IPv4 ] ;
    
    NSDictionary *addresses = [self getIPAddresses];
    NSLog(@"addresses: %@", addresses);
    
    __block NSString *address;
    [searchArray enumerateObjectsUsingBlock:^(NSString *key, NSUInteger idx, BOOL *stop)
     {
         address = addresses[key];
         //筛选出IP地址格式
         if([self isValidatIP:address]) *stop = YES;
     } ];
    return address ? address : @"0.0.0.0";
}

+ (BOOL)isValidatIP:(NSString *)ipAddress {
    if (ipAddress.length == 0) {
        return NO;
    }
    NSString *urlRegEx = @"^([01]?\\d\\d?|2[0-4]\\d|25[0-5])\\."
    "([01]?\\d\\d?|2[0-4]\\d|25[0-5])\\."
    "([01]?\\d\\d?|2[0-4]\\d|25[0-5])\\."
    "([01]?\\d\\d?|2[0-4]\\d|25[0-5])$";
    
    NSError *error;
    NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:urlRegEx options:0 error:&error];
    
    if (regex != nil) {
        NSTextCheckingResult *firstMatch=[regex firstMatchInString:ipAddress options:0 range:NSMakeRange(0, [ipAddress length])];
        
        if (firstMatch) {
            NSRange resultRange = [firstMatch rangeAtIndex:0];
            NSString *result=[ipAddress substringWithRange:resultRange];
            //输出结果
            NSLog(@"%@",result);
            return YES;
        }
    }
    return NO;
}

+ (NSDictionary *)getIPAddresses
{
    NSMutableDictionary *addresses = [NSMutableDictionary dictionaryWithCapacity:8];
    
    // retrieve the current interfaces - returns 0 on success
    struct ifaddrs *interfaces;
    if(!getifaddrs(&interfaces)) {
        // Loop through linked list of interfaces
        struct ifaddrs *interface;
        for(interface=interfaces; interface; interface=interface->ifa_next) {
            if(!(interface->ifa_flags & IFF_UP) /* || (interface->ifa_flags & IFF_LOOPBACK) */ ) {
                continue; // deeply nested code harder to read
            }
            const struct sockaddr_in *addr = (const struct sockaddr_in*)interface->ifa_addr;
            char addrBuf[ MAX(INET_ADDRSTRLEN, INET6_ADDRSTRLEN) ];
            if(addr && (addr->sin_family==AF_INET || addr->sin_family==AF_INET6)) {
                NSString *name = [NSString stringWithUTF8String:interface->ifa_name];
                NSString *type;
                if(addr->sin_family == AF_INET) {
                    if(inet_ntop(AF_INET, &addr->sin_addr, addrBuf, INET_ADDRSTRLEN)) {
                        type = IP_ADDR_IPv4;
                    }
                } else {
                    const struct sockaddr_in6 *addr6 = (const struct sockaddr_in6*)interface->ifa_addr;
                    if(inet_ntop(AF_INET6, &addr6->sin6_addr, addrBuf, INET6_ADDRSTRLEN)) {
                        type = IP_ADDR_IPv6;
                    }
                }
                if(type) {
                    NSString *key = [NSString stringWithFormat:@"%@/%@", name, type];
                    addresses[key] = [NSString stringWithUTF8String:addrBuf];
                }
            }
        }
        // Free memory
        freeifaddrs(interfaces);
    }
    return [addresses count] ? addresses : nil;
}

• 在其他设备中访问该地址即可

let address = IPHelper.deviceIPAdress()
let port = webServer?.port
http://\(address):\(port)/

• 备注：
  • 确保设备在同一局域网
  • 上传时勿关闭该页面

Game Over

局域网中，设备作为server，其他设备作为client，简单的HTTP方式上传文件到server，初始配置的路径即为server接收后存放文件的路径