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postinmemory.c 3.4 KB

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  1. /***************************************************************************
  2. * _ _ ____ _
  3. * Project ___| | | | _ \| |
  4. * / __| | | | |_) | |
  5. * | (__| |_| | _ <| |___
  6. * \___|\___/|_| \_\_____|
  7. *
  8. * Copyright (C) 1998 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
  9. *
  10. * This software is licensed as described in the file COPYING, which
  11. * you should have received as part of this distribution. The terms
  12. * are also available at https://curl.haxx.se/docs/copyright.html.
  13. *
  14. * You may opt to use, copy, modify, merge, publish, distribute and/or sell
  15. * copies of the Software, and permit persons to whom the Software is
  16. * furnished to do so, under the terms of the COPYING file.
  17. *
  18. * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  19. * KIND, either express or implied.
  20. *
  21. ***************************************************************************/
  22. /* <DESC>
  23. * Make a HTTP POST with data from memory and receive response in memory.
  24. * </DESC>
  25. */
  26. #include <stdio.h>
  27. #include <stdlib.h>
  28. #include <string.h>
  29. #include <curl/curl.h>
  30. struct MemoryStruct {
  31. char *memory;
  32. size_t size;
  33. };
  34. static size_t
  35. WriteMemoryCallback(void *contents, size_t size, size_t nmemb, void *userp)
  36. {
  37. size_t realsize = size * nmemb;
  38. struct MemoryStruct *mem = (struct MemoryStruct *)userp;
  39. char *ptr = realloc(mem->memory, mem->size + realsize + 1);
  40. if(!ptr) {
  41. /* out of memory! */
  42. printf("not enough memory (realloc returned NULL)\n");
  43. return 0;
  44. }
  45. mem->memory = ptr;
  46. memcpy(&(mem->memory[mem->size]), contents, realsize);
  47. mem->size += realsize;
  48. mem->memory[mem->size] = 0;
  49. return realsize;
  50. }
  51. int main(void)
  52. {
  53. CURL *curl;
  54. CURLcode res;
  55. struct MemoryStruct chunk;
  56. static const char *postthis = "Field=1&Field=2&Field=3";
  57. chunk.memory = malloc(1); /* will be grown as needed by realloc above */
  58. chunk.size = 0; /* no data at this point */
  59. curl_global_init(CURL_GLOBAL_ALL);
  60. curl = curl_easy_init();
  61. if(curl) {
  62. curl_easy_setopt(curl, CURLOPT_URL, "https://www.example.org/");
  63. /* send all data to this function */
  64. curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, WriteMemoryCallback);
  65. /* we pass our 'chunk' struct to the callback function */
  66. curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void *)&chunk);
  67. /* some servers don't like requests that are made without a user-agent
  68. field, so we provide one */
  69. curl_easy_setopt(curl, CURLOPT_USERAGENT, "libcurl-agent/1.0");
  70. curl_easy_setopt(curl, CURLOPT_POSTFIELDS, postthis);
  71. /* if we don't provide POSTFIELDSIZE, libcurl will strlen() by
  72. itself */
  73. curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE, (long)strlen(postthis));
  74. /* Perform the request, res will get the return code */
  75. res = curl_easy_perform(curl);
  76. /* Check for errors */
  77. if(res != CURLE_OK) {
  78. fprintf(stderr, "curl_easy_perform() failed: %s\n",
  79. curl_easy_strerror(res));
  80. }
  81. else {
  82. /*
  83. * Now, our chunk.memory points to a memory block that is chunk.size
  84. * bytes big and contains the remote file.
  85. *
  86. * Do something nice with it!
  87. */
  88. printf("%s\n",chunk.memory);
  89. }
  90. /* always cleanup */
  91. curl_easy_cleanup(curl);
  92. /* we're done with libcurl, so clean it up */
  93. curl_global_cleanup();
  94. }
  95. free(chunk.memory);
  96. return 0;
  97. }