Question

我创建了一个management command，我想从ftp下载csv文件并在必要时更新数据库。

我的代码如下：

class Command(BaseCommand):       
    @staticmethod
    def update_database(row):
        code = row['CODE']
        vat_number = row['BTWNR']
        if code != "" and vat_number != "":
            # pdb.set_trace()
            print("Code: {0} --- BTW: {1}").format(code, vat_number)

    def read_file(self):
        path_to_relations_csv_file = "{0}/{1}".format(destination, file_name)
        with open(path_to_relations_csv_file) as csvfile:
            relations_reader = csv.DictReader(csvfile, delimiter=';')    
            for row in relations_reader:    
                self.update_database(row)

    def handle(self, *args, **options):

        # Open ftp connection
        ftp = ftplib.FTP(ftp_host, ftp_username, ftp_password)

        try:
            ftp.cwd(source)  # Goes to remote folder where the relations file is
            os.chdir(destination)  # Goes to local folder where the relations file will be downloaded
            print("Switched to the directory successful. Current directory: {}".format(destination))
        except OSError:
            pass
        except ftplib.error_perm:
            print("Error: could not change to {0}".format(source))
            sys.exit("Ending Application")

        try:
            # Get the file
            relations = open(file_name, "wb")  # Opens the remote file
            ftp.retrbinary('RETR {0}'.format(file_name), relations.write)  # Writes to the local file
            print("File {0} downloaded successfully.".format(file_name))

            relations.close()  # Closes the local file
            print("Local file closed.")
            ftp.quit()  # Closes the ftp connection
            print("FTP Connection quited.")

            try:
                self.read_file()
            except:
                print("Error: Unable to read the file.")
        except:
            print("Error: File {0} could not be downloaded.".format(file_name))

但是在read_file方法中，for循环给了我错误。如果我在for循环之前放置pdb.set_trace()，我可以看到relations_reader是<csv.DictReader object at 0x10e67a6a0>，因此看起来没问题，但是如果我尝试循环它，它会转到except并且它执行print("Error: Unable to read the file.")

路径正确。

如果使用python file_name.py执行相同的代码作为单独的文件而不是python manage.py file_name的命令，则一切正常。

知道我做错了什么吗？

Answer 1

iterator should return strings, not bytes (did you open the file in text mode?)表示您需要以其他方式打开CSV，而不是以您的方式打开CSV。

要解决此问题，请将打开模式和编码更改为适合您的csv文件的模式

open(path_to_relations_csv_file, "rt", encoding='utf-8') as csvfile:

如何在Python / Django中循环遍历csv文件

1 个答案: