From 14b2038f09bb98d78ed06a107905bef75cbc5f35 Mon Sep 17 00:00:00 2001
From: Fufu Fang <fangfufu2003@gmail.com>
Date: Fri, 20 Jul 2018 15:38:44 +0100
Subject: [PATCH] added partial download script

---
 data.h |  5 ++++-
 link.c | 38 +++++++++++++++++++++++++++++++-------
 link.h |  4 ++++
 main.c |  3 +--
 test.c | 21 ++++++---------------
 test.h |  3 +--
 6 files changed, 47 insertions(+), 27 deletions(-)

diff --git a/data.h b/data.h
index 8fc3129..de32a19 100644
--- a/data.h
+++ b/data.h
@@ -9,12 +9,15 @@
 
 #define URL_LEN_MAX 2048
 #define LINK_LEN_MAX 255
+#define HTTP_OK 200
 
 /** \brief the link type */
 typedef enum {
+    LINK_HEAD = 'H',
     LINK_DIR = 'D',
     LINK_FILE = 'F',
-    LINK_UNKNOWN = 'U'
+    LINK_UNKNOWN = 'U',
+    LINK_INVALID = 'I'
 } LinkType;
 
 /** \brief link data type */
diff --git a/link.c b/link.c
index 45129a2..e4c6d49 100644
--- a/link.c
+++ b/link.c
@@ -37,6 +37,7 @@ Link *Link_new(const char *p_url)
     curl_easy_setopt(link->curl, CURLOPT_WRITEFUNCTION, WriteMemoryCallback);
     curl_easy_setopt(link->curl, CURLOPT_WRITEDATA, (void *)link);
     curl_easy_setopt(link->curl, CURLOPT_USERAGENT, "mount-http-dir/libcurl");
+    curl_easy_setopt(link->curl, CURLOPT_VERBOSE, 1);
 
     return link;
 }
@@ -49,6 +50,22 @@ void Link_free(Link *link)
     link = NULL;
 }
 
+int Link_download(Link *link, size_t start, size_t end)
+{
+    CURL *curl = link->curl;
+    char range_str[64];
+    snprintf(range_str, sizeof(range_str), "%lu-%lu", start, end);
+
+    curl_easy_setopt(curl, CURLOPT_NOBODY, 0);
+    curl_easy_setopt(curl, CURLOPT_RANGE, range_str);
+
+    curl_easy_perform(link->curl);
+
+    long http_resp;
+    curl_easy_getinfo(link->curl, CURLINFO_RESPONSE_CODE, &http_resp);
+    return http_resp;
+}
+
 LinkTable *LinkTable_new(const char *url)
 {
     LinkTable *linktbl = calloc(1, sizeof(LinkTable));
@@ -56,6 +73,7 @@ LinkTable *LinkTable_new(const char *url)
     /* populate the base URL */
     LinkTable_add(linktbl, Link_new(url));
     Link *head_link = linktbl->links[0];
+    head_link->type = LINK_HEAD;
     curl_easy_setopt(head_link->curl, CURLOPT_URL, url);
 
     /* start downloading the base URL */
@@ -111,14 +129,20 @@ void LinkTable_fill(LinkTable *linktbl)
             free(url);
             curl_easy_setopt(curl, CURLOPT_NOBODY, 1);
             curl_easy_perform(curl);
-            double cl;
-            curl_easy_getinfo(curl, CURLINFO_CONTENT_LENGTH_DOWNLOAD, &cl);
-            if (cl == -1) {
-                this_link->content_length = 0;
-                this_link->type = LINK_DIR;
+            long http_resp;
+            curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE, &http_resp);
+            if (http_resp == HTTP_OK) {
+                double cl;
+                curl_easy_getinfo(curl, CURLINFO_CONTENT_LENGTH_DOWNLOAD, &cl);
+                if (cl == -1) {
+                    this_link->content_length = 0;
+                    this_link->type = LINK_DIR;
+                } else {
+                    this_link->content_length = cl;
+                    this_link->type = LINK_FILE;
+                }
             } else {
-                this_link->content_length = cl;
-                this_link->type = LINK_FILE;
+                this_link->type = LINK_INVALID;
             }
         }
     }
diff --git a/link.h b/link.h
index 2645d27..27899c7 100644
--- a/link.h
+++ b/link.h
@@ -13,6 +13,10 @@ Link *Link_new();
 /** \brief free a Link */
 void Link_free(Link *link);
 
+/** \brief download a link */
+int Link_download(Link *link, size_t start, size_t end);
+
+
 /** \brief make a new LinkTable */
 LinkTable *LinkTable_new(const char *url);
 
diff --git a/main.c b/main.c
index 7b7bfc1..127f46f 100644
--- a/main.c
+++ b/main.c
@@ -19,8 +19,7 @@ int main(int argc, char** argv)
 
     init();
 
-    gumbo_test();
-    url_test();
+    link_test();
 
     return 0;
 }
diff --git a/test.c b/test.c
index b1a9f45..62689bd 100644
--- a/test.c
+++ b/test.c
@@ -7,26 +7,17 @@
 #include "link.h"
 #include "test.h"
 
-void url_test()
-{
-    printf("--- start of url_test ---\n");
-    char *url1 = "http://www.google.com/";
-    char *url2 = "http://www.google.com";
-    char *cat_url1 = url_append(url1, "fangfufu");
-    char *cat_url2 = url_append(url2, "fangfufu");
-    printf("%d %s\n", (int) strlen(cat_url1), cat_url1);
-    printf("%d %s\n", (int) strlen(cat_url2), cat_url2);
-    printf("--- end of url_test ---\n\n");
-}
 
-void gumbo_test()
+void link_test()
 {
-    printf("--- start of gumbo_test ---\n");
+    printf("--- start of link_test ---\n");
 
     LinkTable *linktbl = LinkTable_new(
-        "https://www.fangfufu.co.uk/~fangfufu/test/");
+        "http://127.0.0.1/~fangfufu/");
 
     LinkTable_print(linktbl);
+    Link_download(linktbl->links[1], 1, 20);
+    printf(linktbl->links[1]->body);
     LinkTable_free(linktbl);
-    printf("--- end of gumbo_test ---\n\n");
+    printf("\n--- end of link_test ---\n\n");
 }
diff --git a/test.h b/test.h
index 848ab9a..be716dc 100644
--- a/test.h
+++ b/test.h
@@ -1,7 +1,6 @@
 #ifndef TEST_H
 #define TEST_H
-void url_test();
 
-void gumbo_test();
+void link_test();
 
 #endif