iOS自定義log並寫入文件

時間 2019-11-07

標籤 ios 自定義 log 寫入文件欄目 iOS 简体版

原文原文鏈接

前言

iOS開發中，不少狀況須要使用到log打印，本文主要講解如何將打印寫入文件，而且不影響控制檯的正常打印。git

常見方法

NSString *documentDirectory = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
NSDateFormatter *dateformat = [[NSDateFormatter  alloc]init];
[dateformat setDateFormat:@"yyyy-MM-dd-HH-mm-ss"];
NSString *fileName = [NSString stringWithFormat:@"LOG-%@.txt",[dateformat stringFromDate:[NSDate date]]];
NSString *logFilePath = [documentDirectory stringByAppendingPathComponent:fileName];
    // 先刪除已經存在的文件
NSFileManager *defaultManager = [NSFileManager defaultManager];
[defaultManager removeItemAtPath:logFilePath error:nil];
    // 將log輸入到文件
 freopen([logFilePath cStringUsingEncoding:NSASCIIStringEncoding], "a+", stdout);  
freopen([logFilePath cStringUsingEncoding:NSASCIIStringEncoding], "a+", stderr);
複製代碼

這種寫法雖然能夠將打印攔截寫入文件，可是控制檯就沒有了打印，不方便調試。github

自定義方法

考慮到開發總須要查看控制檯打印，實際應用中須要寫入多個文件等狀況，咱們自定義一個打印類來寫日誌文件。具體代碼以下bash

static NSFileHandle *CLLogFileHandle()
{
    static NSFileHandle *fileHandle = nil;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^
                  {
                      NSFileManager *fileManager = [[NSFileManager alloc] init];
                      
                      NSString *documentsDirectory = [Tools pathDocuments];
                      
                      NSString *currentFilePath = [documentsDirectory stringByAppendingPathComponent:@"application-0.log"];
                      NSString *oldestFilePath = [documentsDirectory stringByAppendingPathComponent:@"application-60.log"];
                      
                      //60文件存在，刪除
                      if ([fileManager fileExistsAtPath:oldestFilePath]){
                          [fileManager removeItemAtPath:oldestFilePath error:nil];
                      }
                      //遍歷文件，將文件編號日後移動，新增第0的一個文件
                      for (int i = 60 - 1; i >= 0; i--) {
                          NSString *filePath = [documentsDirectory stringByAppendingPathComponent:[NSString stringWithFormat:@"application-%d.log", i]];
                          NSString *nextFilePath = [documentsDirectory stringByAppendingPathComponent:[NSString stringWithFormat:@"application-%d.log", i + 1]];
                          if ([fileManager fileExistsAtPath:filePath])
                          {
                              [fileManager moveItemAtPath:filePath toPath:nextFilePath error:nil];
                          }
                      }
                      
                      [fileManager createFileAtPath:currentFilePath contents:nil attributes:nil];
                      fileHandle = [NSFileHandle fileHandleForWritingAtPath:currentFilePath];
                      [fileHandle truncateFileAtOffset:0];
                  });
    
    return fileHandle;
}

void CLLogWithFile(NSString *format, ...) {
    va_list L;
    va_start(L, format);
    NSString *message = [[NSString alloc] initWithFormat:format arguments:L];
    NSLog(@"%@", message);
    // 開啓異步子線程，將打印寫入文件
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        NSFileHandle *output = CLLogFileHandle();
        if (output != nil) {
            time_t rawtime;
            struct tm timeinfo;
            char buffer[64];
            time(&rawtime);
            localtime_r(&rawtime, &timeinfo);
            struct timeval curTime;
            gettimeofday(&curTime, NULL);
            int milliseconds = curTime.tv_usec / 1000;
            strftime(buffer, 64, "%Y-%m-%d %H:%M", &timeinfo);
            char fullBuffer[128] = { 0 };
            snprintf(fullBuffer, 128, "%s:%2d.%.3d ", buffer, timeinfo.tm_sec, milliseconds);
            [output writeData:[[[NSString alloc] initWithCString:fullBuffer encoding:NSASCIIStringEncoding] dataUsingEncoding:NSUTF8StringEncoding]];
            [output writeData:[message dataUsingEncoding:NSUTF8StringEncoding]];
            static NSData *returnData = nil;
            if (returnData == nil)
                returnData = [@"\n" dataUsingEncoding:NSUTF8StringEncoding];
            [output writeData:returnData];
        }
    });
    va_end(L);
}
複製代碼