1# Sample Server Development
2
3## How to Develop
4
51. Generate an SSL certificate.
6
7	Generate the **serverKey.pem** and **serverCert.cer** files for SSL communication of the sample server.
8
9	```
10	openssl req -newkey rsa:2048 -nodes -keyout serverKey.pem -x509 -days 365 -out serverCert.cer -subj "/C=CN/ST=GD/L=GZ/O=abc/OU=defg/CN=hijk/emailAddress=test.com"
11	```
12
13
14
152. Modify the **bundle.json** file.
16
17	Add **sub_component** to the **build** field.
18
19	```
20	"sub_component": [
21		"//base/update/updateservice/server_sample:testserver",
22		...
23	],
24	```
25
263. Create a code directory.
27
28	Go to the **update_updateservice** directory and run the following commands to create a code directory:
29
30	```
31	mkdir server_sample                            // Create the server_sample folder.
32	touch server_sample/BUILD.gn                   // Create the BUILD.gn file.
33	mkdir server_sample/include                    // Create the include folder to store the header file of the sample server.
34	touch server_process.h                         // Create the server_process.h header file.
35	mkdir server_sample/src                        // Create the src folder to store the C/C++ files of the sample server.
36	touch server_sample/src/server_process.c       // Create the server_process.c file.
37	touch server_sample/src/main.cpp               // Create the main.cpp file.
38	```
39
404. Write the **BUILD.gn** file.
41
42	The **BUILD.gn** file contains two **ohos** components: **ohos_shared_library** file named **libserver_process.z.so** and **ohos_executable** file named **testserver**.
43
44	```
45	import("//build/ohos.gni")
46
47	ohos_shared_library("server_process") {
48		sources = [
49			"//base/update/updateservice/server_sample/src/server_process.c",
50		]
51
52		include_dirs = [
53			"//base/update/updateservice/server_sample/include",
54			"//third_party/openssl/include",
55		]
56
57		deps = [
58			"//base/update/updater/services/log:libupdaterlog",
59			"//third_party/bounds_checking_function:libsec_static",
60			"//third_party/openssl:crypto_source",
61			"//third_party/openssl:ssl_source",
62			"//utils/native/base:utils",
63		]
64
65		part_name = "update_service"
66	}
67
68	ohos_executable("testserver") {
69		sources = [
70			"//base/update/updateservice/server_sample/src/main.cpp",
71		]
72
73		include_dirs = [
74			"//base/update/updateservice/server_sample/include",
75		]
76
77		deps = [
78			"//base/update/updateservice/server_sample:server_process",
79		]
80
81		part_name = "update_service"
82	}
83	```
84
855. Write the **server_process.h** file.
86
87	Declare the sample server APIs in the **server_process.h** file.
88
89	```c++
90	#ifndef __SERVER_PROCESS_H__
91	#define __SERVER_PROCESS_H__
92
93	/*
94	Init: creates a socket environment and presets certain attributes.
95	*/
96	int Init();
97
98	/*
99	SetParam: sets all plug-in parameters.
100	*/
101	int SetParam(const char *key, const char *value);
102
103	/*
104	GetParam: obtains all plug-in parameters.
105	*/
106	int GetParam(const char *key, char *value);
107
108	/*
109	ReverseSetParamCallback: callback.
110	*/
111	int ReverseSetParamCallback(int(*setParam)(const char *key, const char *value));
112
113	/*
114	Open: starts the service.
115	*/
116	int Open();
117
118	/*
119	MainLoop: invoked every 100 ms.
120	*/
121	int MainLoop();
122
123	/*
124	Close: stops the service and releases related resources.
125	*/
126	int Close();
127
128	#endif //__SERVER_PROCESS_H__
129	```
130
1316. Write the **server_process.c** and **main.cpp** files.
132
133	In the **server_process.c** file, mainly declare **respondContent**, the format of the response message returned by the server. Write the **main.cpp** file based on instructions for the common SSL protocol server. Be sure to include related header files and load the **serverKey.pem** and **serverCert.cer** files.
134
135	```c
136	#include "server_process.h"
137
138	#include <netinet/in.h>
139	#include <sys/types.h>
140	#include <sys/socket.h>
141	#include <arpa/inet.h>
142	#include <unistd.h>
143	#include <stdlib.h>
144	#include <string.h>
145	#include <stdio.h>
146
147	#include "openssl/err.h"
148	#include "openssl/ssl.h"
149
150	#define SERVER_PEM "/data/sdcard/serverKey.pem"  // Use an absolute path.
151	#define SERVER_CER "/data/sdcard/serverCert.cer" // Use an absolute path.
152
153	#define LOG_PRINT(fmt, ...) printf("[ServerProcess][%s:%d] " fmt "\n", __func__, __LINE__, ##__VA_ARGS__)
154	#define DO_CHECK(cond, log, ...) \
155		if (!(cond)) {\
156			LOG_PRINT(log);\
157			__VA_ARGS__;\
158			return -1;\
159		}
160
161	// Implement the function by referring to the APIs in the server_process.h file. Pay attention to the format of the response message from the server.
162	respondContent = "{"
163		"\"searchStatus\": 0,"
164		"\"errMsg\": \"success\","
165		"\"checkResults\": [{"
166			"\"versionName\": \"sampleVersionName\","
167			"\"versionCode\": \"sampleVersionCode\","
168			"\"verifyInfo\": \"sampleVerifyInfoSha256Value\","
169			"\"size\": 1234567,"
170			"\"packageType\": 1,"
171			"\"descriptPackageId\": \"abcdefg1234567ABCDEFG\","
172		"}],"
173		"\"descriptInfo\": [{"
174			"\"descriptionType\": 0,"
175			"\"content\": \"This package message is used for sampleContent\""
176		"}]"
177	"}";
178	```
179
1807. Start building.
181
182	The **testserver** and **libserver_process.z.so** files are added to the build output directory.
183
1848. Develop an update package.
185
186	For details, see the [update_packaging_tools repository](https://gitee.com/openharmony/update_packaging_tools).
187
1889. Start the package search server.
189
190	Create a directory that contains only English characters on the development board. Place the **testserver**, **libserver_process.z.so**, **serverCert.cer**, and **serverKey.pem** files in the directory, go to the directory, and run the following command to start the package search server:
191
192	```
193	./testserver ./libserver_process.z.so &
194	```
195