复制并保留以前的输出，以便备份转换后的json数据

Question

我有一个perl脚本，它将json数据转换为perl，并将输出保存在名为teams.txt的文件和名为backup.txt的文件中，teams.txt的输出就是从该文件中复制出来的。以下是脚本/将数据写入文本文件的部分中的两个代码片段：

my %manager_to_directs;
my %user_to_manager;
my @users;
my $url = "https://xxxxxxxxxxxxxx.com/api/v1/reports/active/week";

my $useragent = LWP::UserAgent->new();
my $response = $useragent->get(($url));
if ($response->code !~ "200" || $response->code !~ "204" ){

while ($url && $url ne "Null") {
  my $data = fetch_json($url);
  last if !defined $data;

  $url  = $data->{next};
.
.
.

# write backyard.txt
open my $backyard_fh, ">", "backyard.txt";
foreach my $user (sort keys %user_to_management_chain) {
  my $chain = join ',', @{$user_to_management_chain{$user}};
  print $backyard_fh "$user:$chain\n";
}
close $backyard_fh;

# write teams.txt
open my $team_fh, ">", "teams.txt";
foreach my $user (sort @users) {
  my $followers = $manager_to_followers{$user};
  my $followers_joined = $followers ? join (',', sort @$followers) : "";
  print $team_fh "$user:$followers_joined\n";
}
close $team_fh;

# write backup.txt, backup for teams.txt
open my $backup_fh, ">", "backup.txt";
copy("teams.txt", "backup.txt")
    or die ("Can't copy teams.txt \n");
close $backup_fh;

这几乎完全按照我想要的方式工作，但是现在我一直在测试一个负面的场景，脚本中提供的.json url是假的/不存在的，我必须确保没有创建另一个teams.txt文件，并且backup.txt文件仍然保留在上次执行中。

我通过替换

my $url = "https://xxxxxxxxxxxxxx.com/api/v1/reports/active/week";

使用

my $url = "https://fakeUrl.com/api/v1/reports/active/week";

在这种情况下，404将被通过，程序将失败。在这个测试中，我注意到teams.txt和backyard.txt的内容被擦除了，但是backup.txt文件被擦除了too...and，这是不好的。

我同意每次运行脚本时都会覆盖teams.txt和backyard.txt，但我需要保留backup.txt文件，除非程序成功运行，并且teams.txt中有新内容要复制到backup.txt。

任何我能得到的帮助我都非常感谢！

Answer 1

下面是几乎直接取自模块文档的代码片段。

也许你应该尝试这种方法。

use strict;
use warnings;
use feature 'say';

use LWP::UserAgent ();

my $url = 'https://metacpan.org/pod/HTTP::Tiny';
   $url = 'https://fakeUrl.com/api/v1/reports/active/week';
my $ua = LWP::UserAgent->new(timeout => 10);
$ua->env_proxy;

my $response = $ua->get($url);
my $data; 

if ($response->is_success) {
    $data = $response->decoded_content;
}
else {
    die $response->status_line;
}

# Process further data
say $data;

输出

500 Can't connect to fakeUrl.com:443 (Bad file descriptor) at C:\....\http_lwp.pl line 19.

use strict;
use warnings;
use feature 'say';

use HTTP::Tiny;

my $url = 'https://metacpan.org/pod/HTTP::Tiny';
   $url = 'https://fakeUrl.com/api/v1/reports/active/week';
my $data;

my $response = HTTP::Tiny->new->get($url);

if( $response->{success} ) {
    $data = $response->{content};
} else {
    say "$response->{status} $response->{reason}";
    exit 1;
}

# Process further data
say $data;

输出

403 Forbidden