问题:浏览器与文件服务器如何交互?
浏览器与文件服务器的交互
-
文件浏览
- 点击列表中的文件夹 → 进入子文件夹(展示子文件夹列表)
-
文件下载
- 点击列表中的文件 → 下载目标文件
-
错误处理
- 向服务器发送错误请求 → 浏览不存在的文件夹 / 下载不存在的文件
文件浏览交互实现
实现中的关键概念
-
共享文件夹(root)
- 服务端启动时指定的共享文件夹路径(服务系统中的路径)
-
请求路径(req)
- 文件 / 文件夹 在服务端上相对共享文件夹的路径
-
绝对路径
AbsPath = root + "/" + req
基础函数定义
-
char *GetAbsPath(const char *relative, const char *root)
- 拼接 root 和 relative, 返回绝对路径,返回值需释放 (free)
-
int isDotPath(const char *path)
- 判断 path 是否为特殊路径 “.” 或 “..”
-
int GetEntryCount(const char *path)
- 返回 path 路径下的 (文件 + 文件夹)总数
编程实验:基础函数实现
static char *GetAbsPath(const char *relative, const char *root)
{
int reLen = strlen(relative);
int rootLen = strlen(root);
char *ret = malloc(reLen + rootLen + 2);
if (ret) {
strcpy(ret, root);
if ((relative[0] == '/') && (ret[rootLen-1] == '/')) ret[rootLen - 1] = 0;
if ((relative[0] != '/') && (ret[rootLen-1] != '/')) strcat(ret, "/");
strcat(ret, relative);
}
return ret;
}
static int IsDotPath(const char *path)
{
int ret = -1;
if (path) {
ret = (strcmp(path, ".") == 0) || (strcmp(path, "..") == 0);
}
return ret;
}
static int GetEntryCount(const char *path)
{
int ret = -1;
DIR *dirp = opendir(path);
if (dirp != NULL) {
struct dirent *dp = NULL;
ret = 0;
while ((dp = readdir(dirp)) != NULL) {
if (!IsDotPath(dp->d_name)) {
ret ++;
}
}
}
closedir(dirp);
return ret;
}
关键数据结构定义
enum {
TypeAll = 0x00,
TypeDir = 0x04,
TypeFile = 0x08
};
typdef struct {
const int length;
RowInfo data[];
}FileEntry;
typedef struct {
char link[2048];
char name[255];
char type[32];
char size[32];
char time[32];
}RowInfo;
关键函数定义
-
int MakeEntryItem(RowInfo *item, struct dirent *dp, const char *ap, const char *req);
- 根据 dp 所指向的 文件 或 文件夹 生成 RowInfo 数据结构,成功返回 true, 失败返回 false
-
FileEntry *GetEntry(const char *req, const char *root, int type);
- 获取 root/req 路径下 文件 和 文件夹 所对应的 RowInfo 数组,返回值需释放 (free)
-
char *MakeHTML(const char *req, const char *root);
- 创建 root/req 路径下 文件 和 文件夹 所构成的 HTML 页面,返回值需释放 (free)
服务端实现设计
特殊页面设计
编程实验:文件浏览交互实现
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include "page.h"
#include "response.h"
enum { TypeAll = 0x00, TypeDir = 0x04, TypeFile = 0x08 };
typedef struct
{
const int length;
RowInfo data[];
} FileEntry;
static char* GetAbsPath(const char* relative, const char* root)
{
int reLen = strlen(relative);
int rootLen = strlen(root);
char* ret = malloc(reLen + rootLen + 2);
if( ret ) {
strcpy(ret, root);
if( (relative[0] == '/') && (ret[rootLen-1] == '/') ) ret[rootLen-1] = 0;
if( (relative[0] != '/') && (ret[rootLen-1] != '/') ) strcat(ret, "/");
strcat(ret, relative);
}
return ret;
}
static int IsDotPath(const char* path)
{
int ret = -1;
if( path ) {
ret = (strcmp(path, ".") == 0) || (strcmp(path, "..") == 0);
}
return ret;
}
static int GetEntryCount(const char* path)
{
int ret = -1;
DIR* dirp = opendir(path);
if( dirp != NULL ) {
struct dirent* dp = NULL;
ret = 0;
while( (dp = readdir(dirp)) != NULL ) {
if( !IsDotPath(dp->d_name) ) {
ret++;
}
}
}
closedir(dirp);
return ret;
}
static void SortFileEntry(FileEntry* fe)
{
RowInfo* temp = malloc(sizeof(*temp));
if( fe && temp ) {
int i = 0;
int j = 0;
for(i=0; ilength; i++) {
int min = i;
for(j=i; jlength; j++) {
if( strcmp(fe->data[min].name, fe->data[j].name) > 0 ) {
min = j;
}
}
*temp = fe->data[i];
fe->data[i] = fe->data[min];
fe->data[min] = *temp;
}
}
free(temp);
}
static int MakeEntryItem(RowInfo* item, struct dirent* dp, const char* ap, const char* req)
{
int ret = 0;
char buf[32] = {0};
struct stat sb = {0};
char* path = GetAbsPath(dp->d_name, ap);
if( path && (ret = (stat(path, &sb)) != -1) )
{
strcpy(item->link, req);
(strcmp(req, "/") != 0) ? strcat(item->link, "/") : 0;
strcat(item->link, dp->d_name);
strcpy(item->name, dp->d_name);
if( dp->d_type == TypeFile ) {
strcpy(item->type, "File");
if( sb.st_size size, buf);
strcat(item->size, " Byte");
}
else if( (sb.st_size / 1024) size, buf);
strcat(item->size, " KB");
}
else {
sprintf(buf, "%ld", sb.st_size/1024/1024);
strcpy(item->size, buf);
strcat(item->size, " MB");
}
}
else {
strcpy(item->type, "Folder");
sprintf(buf, "%d", GetEntryCount(path));
strcpy(item->size, buf);
strcat(item->size, " Item");
}
strcpy(item->time, ctime(&sb.st_mtime));
}
free(path);
return ret;
}
static FileEntry* GetEntry(const char* req, const char* root, int type)
{
char* ap = GetAbsPath(req, root);
DIR* dirp = NULL;
FileEntry* ret = NULL;
if( ap && (dirp = opendir(ap)) ) {
const int STEP = 5;
struct dirent* dp = NULL;
int max = 0;
int* pLen = NULL;
ret = malloc(sizeof(*ret));
if( ret ) {
pLen = (int*)&ret->length;
*pLen = 0;
}
while( pLen && ((dp = readdir(dirp)) != NULL) ) {
if( *pLen == max ) {
max = max + STEP;
ret = realloc(ret, sizeof(*ret) + sizeof(RowInfo) * max);
pLen = (int*)&ret->length;
}
if( ret && ((type == TypeAll) || (type == dp->d_type)) ) {
if( !IsDotPath(dp->d_name) && MakeEntryItem(&ret->data[*pLen], dp, ap, req) )
{
*pLen = *pLen + 1;
}
}
}
SortFileEntry(ret);
}
free(ap);
closedir(dirp);
return ret;
}
static char* MakeHTML(const char* req, const char* root)
{
char* ret = NULL;
Table* table = CreateTable();
if( table ) {
FileEntry* fe = NULL;
char* ts = NULL;
char* resp = NULL;
RowInfo* back = NULL;
int i = 0;
if( (strcmp(req, "/") != 0) && (back = calloc(1, sizeof(*back))) ) {
i = strlen(req) - 1;
strcpy(back->link, req);
while( back->link[i] != '/' ) i--;
i ? (back->link[i] = 0) : (back->link[i+1] = 0);
strcpy(back->name, "./..");
strcpy(back->type, "Back..");
table = InsertRow(table, back);
}
free(back);
fe = GetEntry(req, root, TypeDir);
for(i=0; fe && (ilength); i++) {
table = InsertRow(table, &fe->data[i]);
}
free(fe);
fe = GetEntry(req, root, TypeFile);
for(i=0; fe && (ilength); i++) {
table = InsertRow(table, &fe->data[i]);
}
free(fe);
ts = ToTableString(table);
ret = ts ? ToPageString(req, ts) : NULL;
free(ts);
}
FreeTable(table);
return ret;
}
static int Response(TcpClient* client, const char* html)
{
const char* HTTP_FORMAT = "HTTP/1.1 200 OKrn"
"Server:Test Http Serverrn"
"Content-Length:%drn"
"Content-Type:text/htmlrn"
"Connection:closernrn"
"%s";
int ret = 0;
if( html ) {
char* resp = malloc(strlen(HTTP_FORMAT) + strlen(html) + 16);
if( resp ) {
sprintf(resp, HTTP_FORMAT, strlen(html), html);
ret = (TcpClient_SendRaw(client, resp, strlen(resp)) > 0);
}
free(resp);
}
return ret;
}
static int DirReqHandler(TcpClient* client, const char* req, const char* root)
{
char* html = MakeHTML(req, root);
int ret = Response(client, html);
free(html);
return ret;
}
int RequestHandler(TcpClient* client, const char* req, const char* root)
{
int ret = 0;
if( client && req && root ) {
ret = DirReqHandler(client, req, root);
}
return ret;
}
思考
favicon.ico 是什么?如何处理?
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