标准c语言实现cgi通讯录

首先，需要了解CGI是什么。CGI是一种通用网关接口，它允许Web服务器运行外部程序，并将其输出返回给Web浏览器。在实现CGI通讯录时，需要编写一个C程序作为CGI程序，该程序将实现通讯录的添加、删除、修改和查询等功能。

以下是一个简单的CGI通讯录示例程序：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define MAX_NAME_LEN 50
#define MAX_PHONE_LEN 20
#define MAX_EMAIL_LEN 50

struct Contact {
    char name[MAX_NAME_LEN + 1];
    char phone[MAX_PHONE_LEN + 1];
    char email[MAX_EMAIL_LEN + 1];
};

void add_contact(struct Contact *contacts, int *count, char *name, char *phone, char *email) {
    if (*count >= 100) {
        printf("Too many contacts!\n");
        return;
    }
    struct Contact *contact = &contacts[*count];
    strncpy(contact->name, name, MAX_NAME_LEN);
    strncpy(contact->phone, phone, MAX_PHONE_LEN);
    strncpy(contact->email, email, MAX_EMAIL_LEN);
    (*count)++;
    printf("Contact added successfully!\n");
}

void delete_contact(struct Contact *contacts, int *count, char *name) {
    int index = -1;
    for (int i = 0; i < *count; i++) {
        if (strcmp(contacts[i].name, name) == 0) {
            index = i;
            break;
        }
    }
    if (index == -1) {
        printf("Contact not found!\n");
        return;
    }
    for (int i = index; i < *count - 1; i++) {
        contacts[i] = contacts[i + 1];
    }
    (*count)--;
    printf("Contact deleted successfully!\n");
}

void modify_contact(struct Contact *contacts, int *count, char *name, char *phone, char *email) {
    int index = -1;
    for (int i = 0; i < *count; i++) {
        if (strcmp(contacts[i].name, name) == 0) {
            index = i;
            break;
        }
    }
    if (index == -1) {
        printf("Contact not found!\n");
        return;
    }
    struct Contact *contact = &contacts[index];
    strncpy(contact->phone, phone, MAX_PHONE_LEN);
    strncpy(contact->email, email, MAX_EMAIL_LEN);
    printf("Contact modified successfully!\n");
}

void query_contact(struct Contact *contacts, int count, char *name) {
    int index = -1;
    for (int i = 0; i < count; i++) {
        if (strcmp(contacts[i].name, name) == 0) {
            index = i;
            break;
        }
    }
    if (index == -1) {
        printf("Contact not found!\n");
        return;
    }
    struct Contact *contact = &contacts[index];
    printf("Name: %s\nPhone: %s\nEmail: %s\n", contact->name, contact->phone, contact->email);
}

int main(int argc, char *argv[]) {
    struct Contact contacts[100];
    int count = 0;

    char *method = getenv("REQUEST_METHOD");
    if (method == NULL) {
        printf("Invalid request!\n");
        return 1;
    }

    char *query_string = getenv("QUERY_STRING");
    if (query_string == NULL) {
        printf("Invalid request!\n");
        return 1;
    }

    if (strcmp(method, "GET") == 0) {
        char *name = strtok(query_string, "&=");
        char *value = strtok(NULL, "&=");
        char *phone = NULL, *email = NULL;
        while (name != NULL && value != NULL) {
            if (strcmp(name, "name") == 0) {
                value = strtok(NULL, "&=");
                strncpy(contacts[count].name, value, MAX_NAME_LEN);
            } else if (strcmp(name, "phone") == 0) {
                phone = value;
            } else if (strcmp(name, "email") == 0) {
                email = value;
            }
            name = strtok(NULL, "&=");
            value = strtok(NULL, "&=");
        }
        if (phone != NULL && email != NULL) {
            strncpy(contacts[count].phone, phone, MAX_PHONE_LEN);
            strncpy(contacts[count].email, email, MAX_EMAIL_LEN);
            count++;
            printf("Contact added successfully!\n");
        } else if (phone != NULL) {
            query_contact(contacts, count, contacts[count - 1].name);
        } else {
            printf("Invalid request!\n");
        }
    } else if (strcmp(method, "POST") == 0) {
        char *content_type = getenv("CONTENT_TYPE");
        if (content_type == NULL || strcmp(content_type, "application/x-www-form-urlencoded") != 0) {
            printf("Invalid request!\n");
            return 1;
        }
        char *content_length_str = getenv("CONTENT_LENGTH");
        if (content_length_str == NULL) {
            printf("Invalid request!\n");
            return 1;
        }
        int content_length = atoi(content_length_str);
        char *post_data = (char *) malloc(content_length + 1);
        if (post_data == NULL) {
            printf("Out of memory!\n");
            return 1;
        }
        fgets(post_data, content_length + 1, stdin);
        char *name = strtok(post_data, "&=");
        char *value = strtok(NULL, "&=");
        char *phone = NULL, *email = NULL;
        while (name != NULL && value != NULL) {
            if (strcmp(name, "name") == 0) {
                value = strtok(NULL, "&=");
                strncpy(contacts[count].name, value, MAX_NAME_LEN);
            } else if (strcmp(name, "phone") == 0) {
                phone = value;
            } else if (strcmp(name, "email") == 0) {
                email = value;
            }
            name = strtok(NULL, "&=");
            value = strtok(NULL, "&=");
        }
        if (phone != NULL && email != NULL) {
            strncpy(contacts[count].phone, phone, MAX_PHONE_LEN);
            strncpy(contacts[count].email, email, MAX_EMAIL_LEN);
            count++;
            printf("Contact added successfully!\n");
        } else if (phone != NULL) {
            query_contact(contacts, count, contacts[count - 1].name);
        } else {
            printf("Invalid request!\n");
        }
        free(post_data);
    } else {
        printf("Invalid request!\n");
        return 1;
    }

    return 0;
}

该程序使用了标准C语言，实现了添加、删除、修改和查询通讯录的功能。在GET请求中，通过解析QUERY_STRING参数来获取参数值。在POST请求中，通过解析POST数据来获取参数值。其中，使用了CGI环境变量来获取请求方法、请求参数等信息。

该程序实现了一个简单的通讯录功能，但是由于没有进行输入验证和安全检查，存在安全隐患，建议在生产环境中使用时进行安全加固。