>> [Contents] Remote Data Collection Step by Step
Configuration file format
The basic format of the configuration file (* .ini) is as follows:
[device] type = NULL id = 1 [comn] protocol = 0 lenth = 400 filter_min = 120 filter_max = 400 [wifi] ssid = user_ssid_null psk = user_psk_null
[device], [comn], [wifi] These are called sections, and each section contains multiple options (parameters) / items (parameter pairs, similar to the concept of a dictionary), for example: type = NULL, here "Type" is called option, and ('type', 'NULL') is called item. The values of the parameters are stored in string format.
configparser library
Use Python's configparser library to read and write configuration files, configparser official documentation:
https://docs.python.org/3/library/configparser.html#configparser.ConfigParser
Search ConfigParser Objects, this section has a detailed function introduction of the function, the following is a list of commonly used:
| cf = configparser.ConfigParser() | Create configparser instance |
| sections() | Return a list of sections |
| add_section(section) | Add a section |
| remove_section(section) | Delete a section |
| has_section(section) | Returns whether a section exists |
| options(section) | Return a list of options under a section |
| has_option(section, option) | Returns whether an option under a section exists |
| remove_option(section, option) | Delete an option under a section |
| items() | Get all sections, including the default section |
| items(section) | Get all items / parameter pairs under a section |
| read(filenames) | Read a certain configuration file filenames and load it into the ConfigParser instance |
| get(section, option) | Returns the value of an option under a section in string format |
| tinted (section, option) | Returns the value of an option under a section in int format |
| getfloat(section, option) | In float format, return the value of an option under a section |
| getboolean(section, option) | Returns the value of an option under a section in boolean format |
| set(section, option, value) | Set the value of an option under a section |
| write(fileobject) | Write the current ConfigParser instance to the configuration file fileobject |
Generate configuration file
The ConfigParser library is a bit different in Python2 and Python3:
- Python3
Lowercase first letter of configparser library
import configparser
config = configparser.ConfigParser()
Create the file test_config_create_p3.py, copy the following content, save and exit
pi@raspberrypi:~ $ sudo nano test_config_create_p3.py
1 # -*- coding:utf-8 -*- 2 import configparser 3 4 config = configparser.ConfigParser() 5 6 config["device"] = { 7 'type' : 'NULL', 8 'id' : '1' 9 } 10 11 config["comn"] = { 12 'protocol' : '0', 13 'lenth' : '400', 14 'filter_min' : '50', 15 'filter_max' : '400' 16 } 17 18 config["wifi"] = { 19 'ssid' : 'user_ssid_null', 20 'psk' : 'user_psk_null' 21 } 22 23 with open('config.ini', 'w') as cf: 24 config.write(cf)
Run the program:
pi@raspberrypi:~ $ python3 test_config_create_p3.py
Open the generated configuration file config.ini:
pi@raspberrypi:~ $ sudo nano config.ini
The contents of sections and options are correct, but the order of the options under the section is not the same as expected, but this is no problem.
- Python2
Capitalize the first letter of the ConfigParser library
import ConfigParser
config = ConfigParser.ConfigParser()
Only section and option can be added one by one in python2
Create the file test_config_create_p2.py, copy the following content, save and exit
pi@raspberrypi:~ $ sudo nano test_config_create_p2.py
1 # -*- coding:utf-8 -*- 2 import ConfigParser 3 4 config = ConfigParser.ConfigParser() 5 6 config.add_section("device") 7 config.set("device", "type", 'NULL') 8 config.set("device", "id", '1') 9 10 config.add_section("comn") 11 config.set("comn", "protocol", '0' ) 12 config.set("comn", "lenth", '400') 13 config.set("comn", "filter_min", '50' ) 14 config.set("comn", "filter_max", '400' ) 15 16 config.add_section("wifi") 17 config.set("wifi", "ssid", 'user_ssid_null') 18 config.set("wifi", "psk", 'user_psk_null') 19 20 with open('config.ini', 'w') as cf: 21 config.write(cf)
先删掉可能存在的config.ini文件
pi@raspberrypi:~ $ rm -f config.ini
运行程序：
pi@raspberrypi:~ $ python2 test_config_create_p2.py
打开生成的配置文件config.ini：
pi@raspberrypi:~ $ sudo nano config.ini
sections和options的内容都是对的，section下的options的顺序与预期的一致。
读取配置文件
读取配置参数时，先确认section是否存在，如果不存在就添加section，并写入默认配置参数。
这里使用的配置参数主要有两种类型：string和int，分别使用get(section, option)、getint(section, option)去读取参数。
读取完成后把所有的items都打印出来。
1 def GetConfig(filepath): 2 global PRODUCT_TYPE 3 global DEVICE_ID 4 5 global PROTOCOL_TYPE 6 global DB_PARAMS_LENGTH 7 global COMN_FILTER_MIN 8 global COMN_FILTER_MAX 9 10 global WIFI_SSID 11 global WIFI_PASSWORD 12 13 is_new_section = False 14 15 print('>> GetConfig()...') 16 print(filepath) 17 18 config = configparser.ConfigParser() 19 config.read(filepath) 20 21 if "wifi" not in config.sections(): 22 print('>> add config >> wifi...') 23 is_new_section = True 24 config.add_section("wifi") 25 config.set("wifi", "ssid", WIFI_SSID) 26 config.set("wifi", "psk", WIFI_PASSWORD) 27 else: 28 WIFI_SSID = config.get("wifi", "ssid") 29 WIFI_PASSWORD = config.get("wifi", "psk") 30 31 if "device" not in config.sections(): 32 print('>> add config >> device...') 33 is_new_section = True 34 config.add_section("device") 35 config.set("device", "type", PRODUCT_TYPE) 36 config.set("device", "id", str(DEVICE_ID)) 37 else: 38 PRODUCT_TYPE = config.get("device", "type") 39 DEVICE_ID = config.getint("device", "id") 40 41 if "comn" not in config.sections(): 42 print('>> add config >> comn...') 43 is_new_section = True 44 config.add_section("comn") 45 config.set("comn", "protocol", str(PROTOCOL_TYPE) ) 46 config.set("comn", "lenth", str(DB_PARAMS_LENGTH)) 47 config.set("comn", "filter_min", str(COMN_FILTER_MIN) ) 48 config.set("comn", "filter_max", str(COMN_FILTER_MAX) ) 49 else: 50 PROTOCOL_TYPE = config.get("comn", "protocol") 51 DB_PARAMS_LENGTH = config.getint("comn", "lenth") 52 COMN_FILTER_MIN = config.getint("comn", "filter_min") 53 COMN_FILTER_MAX = config.getint("comn", "filter_max") 54 55 print('>> list config items...') 56 for sections in config.sections(): 57 for items in config.items(sections): 58 print(items) 59 60 if True == is_new_section: 61 print('>> new section added, write to config file...') 62 with open(filepath, 'w+') as cf: 63 config.write(cf)
修改配置文件
用set(section, option, value)来设置参数值，可以把所有参数值都用str()强制转换一下。
写入之前先把所有的items都打印出来。
1 def SetConfig(filepath): 2 global WIFI_SSID 3 global WIFI_PASSWORD 4 global PRODUCT_TYPE 5 global DEVICE_ID 6 global PROTOCOL_TYPE 7 global DB_PARAMS_LENGTH 8 global COMN_FILTER_MIN 9 global COMN_FILTER_MAX 10 11 print('>> SetConfig()...') 12 print(filepath) 13 14 config = configparser.ConfigParser() 15 config.read(CONFIG_FILE) 16 17 if "device" not in config.sections(): 18 config.add_section("device") 19 if "comn" not in config.sections(): 20 config.add_section("comn") 21 if "wifi" not in config.sections(): 22 config.add_section("wifi") 23 24 config.set("wifi", "ssid", str(WIFI_SSID)) 25 config.set("wifi", "psk", str(WIFI_PASSWORD)) 26 27 config.set("device", "type", str(PRODUCT_TYPE)) 28 config.set("device", "id", str(DEVICE_ID)) 29 30 config.set("comn", "protocol", str(PROTOCOL_TYPE) ) 31 config.set("comn", "lenth", str(DB_PARAMS_LENGTH)) 32 config.set("comn", "filter_min", str(COMN_FILTER_MIN) ) 33 config.set("comn", "filter_max", str(COMN_FILTER_MAX) ) 34 35 print('>> list config items...') 36 for sections in config.sections(): 37 for items in config.items(sections): 38 print(items) 39 40 print('>> write to config file...') 41 with open(CONFIG_FILE, 'w+') as cf: 42 config.write(cf)
运行测试
使用Python3进行测试（如果用Python2，只需要把库的首字母改成大写的）
创建测试程序test_config.py。SetConfig()、GetConfig()参考上面，这里为了便于阅读省略了。
pi@raspberrypi:~ $ sudo nano test_config.py
这个测试函数里先是把默认的配置参数写入到配置文件并读取，然后再修改配置参数，重新写入到配置文件并读取。程序会打印即将写入配置文件的参数，还有从配置文件中读取到的参数。
1 # -*- coding:utf-8 -*- 2 import configparser 3 4 CONFIG_FILE = '/home/pi/config.ini' 5 6 PRODUCT_TYPE = 'NULL' 7 DEVICE_ID = 1 8 PROTOCOL_TYPE = 0 9 DB_PARAMS_LENGTH = 400 10 COMN_FILTER_MIN = 50 11 COMN_FILTER_MAX = 400 12 WIFI_SSID = 'user_ssid_null' 13 WIFI_PASSWORD = 'user_psk_null' 14 15 #---- 16 def GetConfig(filepath): 17 #### 18 19 #---- 20 def SetConfig(filepath): 21 #### 22 23 #---- 24 def main(): 25 global CONFIG_FILE 26 27 global WIFI_SSID 28 global WIFI_PASSWORD 29 global PRODUCT_TYPE 30 global DEVICE_ID 31 global PROTOCOL_TYPE 32 global DB_PARAMS_LENGTH 33 global COMN_FILTER_MIN 34 global COMN_FILTER_MAX 35 36 SetConfig(CONFIG_FILE) 37 GetConfig(CONFIG_FILE) 38 39 PRODUCT_TYPE = 'ANOTHER_TYPE' 40 DEVICE_ID = 2 41 42 PROTOCOL_TYPE = 1 43 DB_PARAMS_LENGTH = 300 44 COMN_FILTER_MIN = 100 45 COMN_FILTER_MAX = 300 46 47 WIFI_SSID = 'another_user_ssid_null' 48 WIFI_PASSWORD = 'another_user_psk_null' 49 50 SetConfig(CONFIG_FILE) 51 GetConfig(CONFIG_FILE) 52 53 if __name__ == '__main__': 54 main()
Run
pi @ raspberrypi with Python3: ~ $ python3 test_config.py
The first is to write the default configuration parameters and read the results, as expected:
After that, the configuration parameters were modified, and the results of writing and reading were consistent with expectations:
